diff --git a/dom/file/ipc/PRemoteLazyInputStream.ipdl b/dom/file/ipc/PRemoteLazyInputStream.ipdl
index 8db41db49162..82fab20cdbcf 100644
--- a/dom/file/ipc/PRemoteLazyInputStream.ipdl
+++ b/dom/file/ipc/PRemoteLazyInputStream.ipdl
@@ -6,7 +6,6 @@ include IPCStream;
 
 namespace mozilla {
 
-[ChildProc=any]
 protocol PRemoteLazyInputStream
 {
 parent:
diff --git a/dom/fs/shared/PFileSystemAccessHandleControl.ipdl b/dom/fs/shared/PFileSystemAccessHandleControl.ipdl
index d74c7c4b4e2f..1380a50e028d 100644
--- a/dom/fs/shared/PFileSystemAccessHandleControl.ipdl
+++ b/dom/fs/shared/PFileSystemAccessHandleControl.ipdl
@@ -7,7 +7,6 @@ using struct mozilla::void_t from "mozilla/ipc/IPCCore.h";
 namespace mozilla {
 namespace dom {
 
-[ChildProc=anydom]
 async protocol PFileSystemAccessHandleControl
 {
  parent:
diff --git a/dom/fs/shared/PFileSystemManager.ipdl b/dom/fs/shared/PFileSystemManager.ipdl
index 9058820fd245..0542465a81be 100644
--- a/dom/fs/shared/PFileSystemManager.ipdl
+++ b/dom/fs/shared/PFileSystemManager.ipdl
@@ -247,7 +247,6 @@ union FileSystemMoveEntryResponse
 
 }  // namespace fs
 
-[ChildProc=anydom]
 async protocol PFileSystemManager
 {
   manages PFileSystemAccessHandle;
diff --git a/dom/ipc/PContent.ipdl b/dom/ipc/PContent.ipdl
index 9bf1b697d2a4..5f045e9f3729 100644
--- a/dom/ipc/PContent.ipdl
+++ b/dom/ipc/PContent.ipdl
@@ -479,7 +479,7 @@ union PClipboardReadRequestOrError {
  * and a content process. There is exactly one PContentParent/PContentChild pair
  * for each content process.
  */
-[NestedUpTo=inside_cpow, NeedsOtherPid, ChildProc=Content]
+[NestedUpTo=inside_cpow, NeedsOtherPid]
 sync protocol PContent
 {
     manages PBrowser;
diff --git a/dom/ipc/PInProcess.ipdl b/dom/ipc/PInProcess.ipdl
index 4c2d7ba548a8..fc1dc92e180b 100644
--- a/dom/ipc/PInProcess.ipdl
+++ b/dom/ipc/PInProcess.ipdl
@@ -21,7 +21,6 @@ namespace dom {
  * `mozilla::dom::InProcess{Parent, Child}::Singleton()` should be used to get
  * an instance of this actor.
  */
-[ChildProc=Parent]
 async protocol PInProcess
 {
   manages PExtensions;
diff --git a/dom/ipc/PJSOracle.ipdl b/dom/ipc/PJSOracle.ipdl
index 519c579aa4f3..2da50d76df26 100644
--- a/dom/ipc/PJSOracle.ipdl
+++ b/dom/ipc/PJSOracle.ipdl
@@ -9,7 +9,6 @@ namespace mozilla {
 namespace dom {
 
 // PJSOracle is a top-level actor which manages PJSValidator
-[ChildProc=Utility]
 async protocol PJSOracle {
   manages PJSValidator;
 
diff --git a/dom/ipc/PProcessHangMonitor.ipdl b/dom/ipc/PProcessHangMonitor.ipdl
index 290f9b157baf..5a85003773fc 100644
--- a/dom/ipc/PProcessHangMonitor.ipdl
+++ b/dom/ipc/PProcessHangMonitor.ipdl
@@ -23,7 +23,7 @@ struct SlowScriptData
   double duration;
 };
 
-[ChildImpl=virtual, ParentImpl=virtual, ChildProc=Content]
+[ChildImpl=virtual, ParentImpl=virtual]
 protocol PProcessHangMonitor
 {
 parent:
diff --git a/dom/media/gmp/PGMP.ipdl b/dom/media/gmp/PGMP.ipdl
index 69db40a06a47..b3dcd9a64567 100644
--- a/dom/media/gmp/PGMP.ipdl
+++ b/dom/media/gmp/PGMP.ipdl
@@ -24,7 +24,7 @@ using mozilla::dom::NativeThreadId from "mozilla/dom/NativeThreadId.h";
 namespace mozilla {
 namespace gmp {
 
-[NeedsOtherPid, NestedUpTo=inside_sync, ChildImpl="GMPChild", ParentImpl="GMPParent", ChildProc=GMPlugin]
+[NeedsOtherPid, NestedUpTo=inside_sync, ChildImpl="GMPChild", ParentImpl="GMPParent"]
 sync protocol PGMP
 {
   manages PGMPTimer;
diff --git a/dom/media/gmp/PGMPContent.ipdl b/dom/media/gmp/PGMPContent.ipdl
index 20b59932ce1d..db47aadc62ea 100644
--- a/dom/media/gmp/PGMPContent.ipdl
+++ b/dom/media/gmp/PGMPContent.ipdl
@@ -16,7 +16,7 @@ include "GMPContentChild.h";
 namespace mozilla {
 namespace gmp {
 
-[NeedsOtherPid, ChildImpl="GMPContentChild", ParentImpl=virtual, ParentProc=anydom, ChildProc=GMPlugin]
+[NeedsOtherPid, ChildImpl="GMPContentChild", ParentImpl=virtual]
 sync protocol PGMPContent
 {
   manages PGMPVideoDecoder;
diff --git a/dom/media/gmp/PGMPService.ipdl b/dom/media/gmp/PGMPService.ipdl
index 11e13945ac29..10e6cc1b1ffb 100644
--- a/dom/media/gmp/PGMPService.ipdl
+++ b/dom/media/gmp/PGMPService.ipdl
@@ -23,7 +23,7 @@ struct GMPLaunchResult {
   nsCString errorDescription;
 };
 
-[NeedsOtherPid, ChildImpl=virtual, ParentImpl=virtual, ChildProc=Content]
+[NeedsOtherPid, ChildImpl=virtual, ParentImpl=virtual]
 async protocol PGMPService
 {
 parent:
diff --git a/dom/media/ipc/PRDD.ipdl b/dom/media/ipc/PRDD.ipdl
index 715ed7f502df..e18f65edafab 100644
--- a/dom/media/ipc/PRDD.ipdl
+++ b/dom/media/ipc/PRDD.ipdl
@@ -41,7 +41,7 @@ namespace mozilla {
 // (RemoteDataDecoder) process. There is one instance of this protocol,
 // with the RDDParent living on the main thread of the RDD process and
 // the RDDChild living on the main thread of the UI process.
-[NeedsOtherPid, ParentProc=RDD, ChildProc=Parent]
+[NeedsOtherPid]
 protocol PRDD
 {
 parent:
diff --git a/dom/media/ipc/PRemoteDecoderManager.ipdl b/dom/media/ipc/PRemoteDecoderManager.ipdl
index 8997face2c4d..e92e1088da89 100644
--- a/dom/media/ipc/PRemoteDecoderManager.ipdl
+++ b/dom/media/ipc/PRemoteDecoderManager.ipdl
@@ -38,7 +38,7 @@ union RemoteDecoderInfoIPDL
   VideoDecoderInfoIPDL;
 };
 
-[NeedsOtherPid, ParentProc=any, ChildProc=anydom]
+[NeedsOtherPid]
 sync protocol PRemoteDecoderManager
 {
   manages PRemoteDecoder;
diff --git a/dom/media/webrtc/PMediaTransport.ipdl b/dom/media/webrtc/PMediaTransport.ipdl
index e7501ed8140b..496bcefccd60 100644
--- a/dom/media/webrtc/PMediaTransport.ipdl
+++ b/dom/media/webrtc/PMediaTransport.ipdl
@@ -28,7 +28,6 @@ using mozilla::net::NrIceStunAddrArray from "mozilla/net/PStunAddrsParams.h";
 namespace mozilla {
 namespace dom {
 
-[ParentProc=Socket, ChildProc=Content]
 async protocol PMediaTransport {
 #ifdef MOZ_WEBRTC
 parent:
diff --git a/dom/midi/PMIDIManager.ipdl b/dom/midi/PMIDIManager.ipdl
index 42698a9189e1..75d0cb32eaf5 100644
--- a/dom/midi/PMIDIManager.ipdl
+++ b/dom/midi/PMIDIManager.ipdl
@@ -7,7 +7,6 @@ include MIDITypes;
 namespace mozilla {
 namespace dom {
 
-[ChildProc=anydom]
 async protocol PMIDIManager
 {
 parent:
diff --git a/dom/midi/PMIDIPort.ipdl b/dom/midi/PMIDIPort.ipdl
index 917518e91965..fc8369a1b1df 100644
--- a/dom/midi/PMIDIPort.ipdl
+++ b/dom/midi/PMIDIPort.ipdl
@@ -9,7 +9,6 @@ include MIDITypes;
 namespace mozilla {
 namespace dom {
 
-[ChildProc=anydom]
 async protocol PMIDIPort
 {
 parent:
diff --git a/dom/quota/PRemoteQuotaObject.ipdl b/dom/quota/PRemoteQuotaObject.ipdl
index f5172c622e0b..f0221d7b9c96 100644
--- a/dom/quota/PRemoteQuotaObject.ipdl
+++ b/dom/quota/PRemoteQuotaObject.ipdl
@@ -6,7 +6,6 @@ namespace mozilla {
 namespace dom {
 namespace quota {
 
-[ChildProc=Content]
 sync protocol PRemoteQuotaObject
 {
  parent:
diff --git a/dom/quota/test/gtest/PQuotaTest.ipdl b/dom/quota/test/gtest/PQuotaTest.ipdl
index 3ea2d0c3f95a..e4ca37325aeb 100644
--- a/dom/quota/test/gtest/PQuotaTest.ipdl
+++ b/dom/quota/test/gtest/PQuotaTest.ipdl
@@ -6,7 +6,6 @@ namespace mozilla {
 namespace dom {
 namespace quota {
 
-[ParentProc=any, ChildProc=any]
 sync protocol PQuotaTest {
  parent:
   sync Try_Success_CustomErr_QmIpcFail()
diff --git a/dom/system/windows/PWindowsUtils.ipdl b/dom/system/windows/PWindowsUtils.ipdl
index fa5b800f3bf7..411e9bcf9344 100644
--- a/dom/system/windows/PWindowsUtils.ipdl
+++ b/dom/system/windows/PWindowsUtils.ipdl
@@ -10,7 +10,6 @@ namespace mozilla {
 namespace dom {
 
 // Manager of utility actors that run in the windows utility process.
-[ChildProc=Utility]
 protocol PWindowsUtils {
   manages PWindowsLocation;
 
diff --git a/dom/webtransport/shared/PWebTransport.ipdl b/dom/webtransport/shared/PWebTransport.ipdl
index 625632242599..b11b315e482d 100644
--- a/dom/webtransport/shared/PWebTransport.ipdl
+++ b/dom/webtransport/shared/PWebTransport.ipdl
@@ -45,7 +45,6 @@ union StreamResetOrStopSendingError {
   StopSendingError;
 };
 
-[ChildProc=anydom]
 async protocol PWebTransport
 {
  parent:
diff --git a/gfx/ipc/PCanvasManager.ipdl b/gfx/ipc/PCanvasManager.ipdl
index 1ba6a88a422d..113f70da397b 100644
--- a/gfx/ipc/PCanvasManager.ipdl
+++ b/gfx/ipc/PCanvasManager.ipdl
@@ -22,7 +22,7 @@ namespace gfx {
  * compositor process. This protocol should be used to create accelerated
  * canvas instances.
  */
-[NeedsOtherPid, ParentProc=compositor, ChildProc=anydom]
+[NeedsOtherPid]
 sync protocol PCanvasManager
 {
   manages PCanvas;
diff --git a/gfx/ipc/PGPU.ipdl b/gfx/ipc/PGPU.ipdl
index b6e84bf142f7..e17ccf27c07f 100644
--- a/gfx/ipc/PGPU.ipdl
+++ b/gfx/ipc/PGPU.ipdl
@@ -53,7 +53,7 @@ struct LayerTreeIdMapping {
 // This protocol allows the UI process to talk to the GPU process. There is one
 // instance of this protocol, with the GPUParent living on the main thread of
 // the GPU process and the GPUChild living on the main thread of the UI process.
-[NeedsOtherPid, ParentProc=GPU, ChildProc=Parent]
+[NeedsOtherPid]
 sync protocol PGPU
 {
 parent:
diff --git a/gfx/ipc/PVsyncBridge.ipdl b/gfx/ipc/PVsyncBridge.ipdl
index 84fd7d8a1784..b498d8a0af1a 100644
--- a/gfx/ipc/PVsyncBridge.ipdl
+++ b/gfx/ipc/PVsyncBridge.ipdl
@@ -16,7 +16,7 @@ namespace gfx {
 // dedicated thread in the UI process to the compositor thread in the
 // compositor process. The child side exists in the UI process, and the
 // parent side in the GPU process.
-[NeedsOtherPid, ParentProc=GPU, ChildProc=Parent]
+[NeedsOtherPid]
 sync protocol PVsyncBridge
 {
 parent:
diff --git a/gfx/layers/ipc/PAPZInputBridge.ipdl b/gfx/layers/ipc/PAPZInputBridge.ipdl
index 7564757b284f..20a569c1d2a8 100644
--- a/gfx/layers/ipc/PAPZInputBridge.ipdl
+++ b/gfx/layers/ipc/PAPZInputBridge.ipdl
@@ -33,7 +33,6 @@ namespace layers {
  * The parent side lives on the main thread in the GPU process. If there is no
  * GPU process, then this protocol is not instantiated.
  */
-[ParentProc=GPU, ChildProc=Parent]
 sync protocol PAPZInputBridge
 {
 parent:
diff --git a/gfx/layers/ipc/PCompositorManager.ipdl b/gfx/layers/ipc/PCompositorManager.ipdl
index 02045511a7e2..697dd857b350 100644
--- a/gfx/layers/ipc/PCompositorManager.ipdl
+++ b/gfx/layers/ipc/PCompositorManager.ipdl
@@ -59,7 +59,7 @@ union CompositorBridgeOptions {
  * compositor thread for compositor data that is only shared once, rather than
  * per PCompositorBridge instance.
  */
-[NeedsOtherPid, ParentProc=compositor, ChildProc=anydom]
+[NeedsOtherPid]
 sync protocol PCompositorManager
 {
   manages PCompositorBridge;
diff --git a/gfx/layers/ipc/PImageBridge.ipdl b/gfx/layers/ipc/PImageBridge.ipdl
index 8af889d8ac6d..07aed85e57b5 100644
--- a/gfx/layers/ipc/PImageBridge.ipdl
+++ b/gfx/layers/ipc/PImageBridge.ipdl
@@ -26,7 +26,7 @@ namespace layers {
  * frames directly to the compositor thread/process without relying on the main thread
  * which might be too busy dealing with content script.
  */
-[NeedsOtherPid, ParentProc=compositor, ChildProc=anydom]
+[NeedsOtherPid]
 sync protocol PImageBridge
 {
   manages PTexture;
diff --git a/gfx/layers/ipc/PUiCompositorController.ipdl b/gfx/layers/ipc/PUiCompositorController.ipdl
index 5aa75bf7dae8..46b733caa2c7 100644
--- a/gfx/layers/ipc/PUiCompositorController.ipdl
+++ b/gfx/layers/ipc/PUiCompositorController.ipdl
@@ -20,7 +20,7 @@ namespace layers {
  * compositor from the UI thread. Primarily used on Android to coordinate registering and
  * releasing the surface with the compositor.
  */
-[NeedsOtherPid, ParentProc=compositor, ChildProc=Parent]
+[NeedsOtherPid]
 sync protocol PUiCompositorController
 {
 
diff --git a/gfx/layers/ipc/PVideoBridge.ipdl b/gfx/layers/ipc/PVideoBridge.ipdl
index eb9d7dafee69..c4699c7583c9 100644
--- a/gfx/layers/ipc/PVideoBridge.ipdl
+++ b/gfx/layers/ipc/PVideoBridge.ipdl
@@ -21,7 +21,7 @@ namespace layers {
  * The PVideoBridge protocol is used to share textures from the video decoders
  * to the compositor.
  */
-[NeedsOtherPid, ParentProc=compositor, ChildProc=any]
+[NeedsOtherPid]
 sync protocol PVideoBridge
 {
   manages PTexture;
diff --git a/gfx/vr/ipc/PVR.ipdl b/gfx/vr/ipc/PVR.ipdl
index 25d5d57025f9..57fba8c235f0 100644
--- a/gfx/vr/ipc/PVR.ipdl
+++ b/gfx/vr/ipc/PVR.ipdl
@@ -18,7 +18,7 @@ include protocol PVRGPU;
 namespace mozilla {
 namespace gfx {
 
-[NeedsOtherPid, ChildImpl="VRChild", ParentImpl="VRParent", ParentProc=VR, ChildProc=Parent]
+[NeedsOtherPid, ChildImpl="VRChild", ParentImpl="VRParent"]
 async protocol PVR
 {
 parent:
diff --git a/gfx/vr/ipc/PVRGPU.ipdl b/gfx/vr/ipc/PVRGPU.ipdl
index 4fd3ff9d5007..c8bf34234f03 100644
--- a/gfx/vr/ipc/PVRGPU.ipdl
+++ b/gfx/vr/ipc/PVRGPU.ipdl
@@ -11,7 +11,7 @@ namespace gfx {
 
 // The parent process is the VR process.
 // The child process is the GPU process.
-[NeedsOtherPid, ChildImpl="VRGPUChild", ParentImpl="VRGPUParent", ParentProc=VR, ChildProc=GPU]
+[NeedsOtherPid, ChildImpl="VRGPUChild", ParentImpl="VRGPUParent"]
 async protocol PVRGPU
 {
 parent:
diff --git a/gfx/vr/ipc/PVRManager.ipdl b/gfx/vr/ipc/PVRManager.ipdl
index 141464be5894..c79be31c4113 100644
--- a/gfx/vr/ipc/PVRManager.ipdl
+++ b/gfx/vr/ipc/PVRManager.ipdl
@@ -34,7 +34,7 @@ namespace gfx {
  * enumeration and sensor state between the compositor thread and
  * content threads/processes.
  */
-[NeedsOtherPid, ChildImpl="VRManagerChild", ParentImpl="VRManagerParent", ParentProc=compositor, ChildProc=anydom]
+[NeedsOtherPid, ChildImpl="VRManagerChild", ParentImpl="VRManagerParent"]
 sync protocol PVRManager
 {
   manages PVRLayer;
diff --git a/ipc/docs/ipdl.rst b/ipc/docs/ipdl.rst
index cf35a23f6944..de8271dee92e 100644
--- a/ipc/docs/ipdl.rst
+++ b/ipc/docs/ipdl.rst
@@ -351,7 +351,6 @@ one in ``PMyManager.ipdl``:
 
 .. code-block:: cpp
 
-    [ChildProc=Content]
     sync protocol PMyManager {
         manages PMyManaged;
 
@@ -407,12 +406,6 @@ They will be discussed further in `Nested messages`_.
                                response.
 ============================== ================================================
 
-In addition, top-level protocols are annotated with which processes each side
-should be bound into using the ``[ParentProc=*]`` and ``[ChildProc=*]``
-attributes.  The ``[ParentProc]`` attribute is optional, and defaults to the
-``Parent`` process.  The ``[ChildProc]`` attribute is required.  See `Process
-Type Attributes`_ for possible values.
-
 The ``manages`` clause tells IPDL that ``PMyManager`` manages the
 ``PMyManaged`` actor that was previously ``include`` d.  As with any managed
 protocol, it must also be the case that ``PMyManaged.ipdl`` includes
@@ -737,63 +730,8 @@ for use in IPDL files:
                               ``Recv`` methods should be used instead of direct
                               function calls.  *New uses of this attribute are
                               discouraged.*
-``[ChildProc=...]``           Indicates which process the child side of the actor
-                              is expected to be bound in.  This will be release
-                              asserted when creating the actor.  Required for
-                              top-level actors.  See `Process Type Attributes`_
-                              for possible values.
-``[ParentProc=...]``          Indicates which process the parent side of the
-                              actor is expected to be bound in.  This will be
-                              release asserted when creating the actor.
-                              Defaults to ``Parent`` for top-level actors.  See
-                              `Process Type Attributes`_ for possible values.
 ============================= =================================================
 
-.. _Process Type Attributes:
-
-Process Type Attributes
-^^^^^^^^^^^^^^^^^^^^^^^
-
-The following are valid values for the ``[ChildProc=...]`` and
-``[ParentProc=...]`` attributes on protocols, each corresponding to a specific
-process type:
-
-============================= =================================================
-``Parent``                    The primary "parent" or "main" process
-``Content``                   A content process, such as those used to host web
-                              pages, workers, and extensions
-``IPDLUnitTest``              Test-only process used in IPDL gtests
-``GMPlugin``                  Gecko Media Plugin (GMP) process
-``GPU``                       GPU process
-``VR``                        VR process
-``RDD``                       Remote Data Decoder (RDD) process
-``Socket``                    Socket/Networking process
-``RemoteSandboxBroker``       Remote Sandbox Broker process
-``ForkServer``                Fork Server process
-``Utility``                   Utility process
-============================= =================================================
-
-The attributes also support some wildcard values, which can be used when an
-actor can be bound in multiple processes.  If you are adding an actor which
-needs a new wildcard value, please reach out to the IPC team, and we can add one
-for your use-case.  They are as follows:
-
-============================= =================================================
-``any``                       Any process.  If a more specific value is
-                              applicable, it should be preferred where possible.
-``anychild``                  Any process other than ``Parent``.  Often used for
-                              utility actors which are bound on a per-process
-                              basis, such as profiling.
-``compositor``                Either the ``GPU`` or ``Parent`` process.  Often
-                              used for actors bound to the compositor thread.
-``anydom``                    Either the ``Parent`` or a ``Content`` process.
-                              Often used for actors used to implement DOM APIs.
-============================= =================================================
-
-Note that these assertions do not provide security guarantees, and are primarily
-intended for use when auditing and as documentation for how actors are being
-used.
-
 
 The C++ Interface
 -----------------
diff --git a/ipc/glue/PBackground.ipdl b/ipc/glue/PBackground.ipdl
index 94b0079ff7fe..4fea97a535b0 100644
--- a/ipc/glue/PBackground.ipdl
+++ b/ipc/glue/PBackground.ipdl
@@ -80,7 +80,7 @@ using mozilla::camera::CamerasAccessStatus from "mozilla/media/CamerasTypes.h";
 namespace mozilla {
 namespace ipc {
 
-[NeedsOtherPid, ChildImpl=virtual, ParentImpl=virtual, ChildProc=anydom]
+[NeedsOtherPid, ChildImpl=virtual, ParentImpl=virtual]
 sync protocol PBackground
 {
   manages PBackgroundIDBFactory;
diff --git a/ipc/glue/PBackgroundStarter.ipdl b/ipc/glue/PBackgroundStarter.ipdl
index 60fd6a3423c5..c53f47cb75a3 100644
--- a/ipc/glue/PBackgroundStarter.ipdl
+++ b/ipc/glue/PBackgroundStarter.ipdl
@@ -7,7 +7,7 @@ include protocol PBackground;
 namespace mozilla {
 namespace ipc {
 
-[NeedsOtherPid, ChildProc=anydom]
+[NeedsOtherPid]
 async protocol PBackgroundStarter
 {
 parent:
diff --git a/ipc/glue/PUtilityAudioDecoder.ipdl b/ipc/glue/PUtilityAudioDecoder.ipdl
index 74dbbd2c5426..1d43cc3b3331 100644
--- a/ipc/glue/PUtilityAudioDecoder.ipdl
+++ b/ipc/glue/PUtilityAudioDecoder.ipdl
@@ -21,7 +21,6 @@ namespace ipc {
 
 // This protocol allows to run media audio decoding infrastructure on top
 // of the Utility process
-[ParentProc=Utility, ChildProc=Parent]
 protocol PUtilityAudioDecoder
 {
 parent:
diff --git a/ipc/glue/PUtilityProcess.ipdl b/ipc/glue/PUtilityProcess.ipdl
index 585590799f3e..afc6a461abf4 100644
--- a/ipc/glue/PUtilityProcess.ipdl
+++ b/ipc/glue/PUtilityProcess.ipdl
@@ -45,8 +45,7 @@ namespace ipc {
 // one instance of this protocol, with the UtilityProcessParent living on the main thread
 // of the main process and the UtilityProcessChild living on the main thread of the Utility
 // process.
-[NeedsOtherPid, ChildProc=Utility]
-protocol PUtilityProcess
+[NeedsOtherPid] protocol PUtilityProcess
 {
 parent:
   async InitCrashReporter(NativeThreadId threadId);
diff --git a/ipc/glue/ProtocolUtils.h b/ipc/glue/ProtocolUtils.h
index 7d1586d9ed99..6da187c2fd0a 100644
--- a/ipc/glue/ProtocolUtils.h
+++ b/ipc/glue/ProtocolUtils.h
@@ -309,13 +309,17 @@ class IProtocol : public HasResultCodes {
 
   // Called when IPC has acquired its first reference to the actor. This method
   // may take references which will later be freed by `ActorDealloc`.
-  virtual void ActorAlloc() = 0;
+  virtual void ActorAlloc() {}
 
   // Called when IPC has released its final reference to the actor. It will call
   // the dealloc method, causing the actor to be actually freed.
   //
   // The actor has been freed after this method returns.
-  virtual void ActorDealloc() = 0;
+  virtual void ActorDealloc() {
+    if (Manager()) {
+      Manager()->DeallocManagee(mProtocolId, this);
+    }
+  }
 
   static const int32_t kNullActorId = 0;
   static const int32_t kFreedActorId = 1;
diff --git a/ipc/ipdl/ipdl/ast.py b/ipc/ipdl/ipdl/ast.py
index ff083cf62858..e50cbb5c655e 100644
--- a/ipc/ipdl/ipdl/ast.py
+++ b/ipc/ipdl/ipdl/ast.py
@@ -316,15 +316,6 @@ class Protocol(NamespacedNode):
             return attr.value
         return None
 
-    def procAttribute(self, side):
-        assert side in ("parent", "child")
-        attr = self.attributes.get(side.capitalize() + "Proc")
-        if attr is not None:
-            return attr.value
-        elif side == "parent" and len(self.managers) == 0:
-            return "Parent"  # Default for toplevel actors
-        return None
-
 
 class StructField(Node):
     def __init__(self, loc, type, name):
diff --git a/ipc/ipdl/ipdl/cxx/ast.py b/ipc/ipdl/ipdl/cxx/ast.py
index a4aba985717b..3b9448859b0f 100644
--- a/ipc/ipdl/ipdl/cxx/ast.py
+++ b/ipc/ipdl/ipdl/cxx/ast.py
@@ -594,7 +594,7 @@ def make_enum(name, members_str):
     return type(name, (), members_dict)
 
 
-MethodSpec = make_enum("MethodSpec", "NONE VIRTUAL PURE OVERRIDE STATIC FINAL")
+MethodSpec = make_enum("MethodSpec", "NONE VIRTUAL PURE OVERRIDE STATIC")
 
 
 class MethodDecl(Node):
diff --git a/ipc/ipdl/ipdl/cxx/cgen.py b/ipc/ipdl/ipdl/cxx/cgen.py
index 43fba4bf990a..fecb90e97be1 100644
--- a/ipc/ipdl/ipdl/cxx/cgen.py
+++ b/ipc/ipdl/ipdl/cxx/cgen.py
@@ -265,8 +265,6 @@ class CxxCodeGen(CodePrinter, Visitor):
 
         if md.methodspec == MethodSpec.OVERRIDE:
             self.write(" override")
-        elif md.methodspec == MethodSpec.FINAL:
-            self.write(" final")
         elif md.methodspec == MethodSpec.PURE:
             self.write(" = 0")
 
diff --git a/ipc/ipdl/ipdl/lower.py b/ipc/ipdl/ipdl/lower.py
index d12198507d89..c6345419d165 100644
--- a/ipc/ipdl/ipdl/lower.py
+++ b/ipc/ipdl/ipdl/lower.py
@@ -3829,27 +3829,6 @@ class _GenerateProtocolActorCode(ipdl.ast.Visitor):
 
         self.cls.addstmts([dtor, Whitespace.NL])
 
-        # ActorAlloc() and ActorDealloc()
-        actoralloc = MethodDefn(MethodDecl("ActorAlloc", methodspec=MethodSpec.FINAL))
-        actordealloc = MethodDefn(
-            MethodDecl("ActorDealloc", methodspec=MethodSpec.FINAL)
-        )
-
-        # Assert process type in ActorAlloc
-        procattr = p.procAttribute(self.side)
-        if procattr not in ("any", None):
-            if procattr == "anychild":
-                procattr_assertion = "!XRE_IsParentProcess()"
-            elif procattr == "anydom":
-                procattr_assertion = "XRE_IsParentProcess() || XRE_IsContentProcess()"
-            elif procattr == "compositor":
-                procattr_assertion = "XRE_IsParentProcess() || XRE_IsGPUProcess()"
-            else:
-                procattr_assertion = "XRE_Is%sProcess()" % procattr
-            actoralloc.addcode(
-                "MOZ_RELEASE_ASSERT(${assertion});\n", assertion=procattr_assertion
-            )
-
         if ptype.isRefcounted():
             if not ptype.isToplevel():
                 self.cls.addcode(
@@ -3857,23 +3836,14 @@ class _GenerateProtocolActorCode(ipdl.ast.Visitor):
                     NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
                     """
                 )
-            # Perform AddRef/Release in ActorAlloc/ActorDealloc if refcounted.
-            actoralloc.addcode("AddRef();\n")
-            actordealloc.addcode("Release();\n")
-        elif not ptype.isToplevel():
-            # If we're a managed actor with [ManualDealloc], use DeallocManagee
-            # to invoke the relevant Dealloc method.
-            actordealloc.addcode(
+            self.cls.addstmt(Label.PROTECTED)
+            self.cls.addcode(
+                """
+                void ActorAlloc() final { AddRef(); }
+                void ActorDealloc() final { Release(); }
                 """
-                if (Manager()) {
-                    Manager()->DeallocManagee(${protocolId}, this);
-                }
-                """,
-                protocolId=_protocolId(ptype),
             )
 
-        self.cls.addstmts([Label.PROTECTED, actoralloc, actordealloc])
-
         self.cls.addstmt(Label.PUBLIC)
         if ptype.hasOtherPid():
             otherpidmeth = MethodDefn(
diff --git a/ipc/ipdl/ipdl/type.py b/ipc/ipdl/ipdl/type.py
index 23646aaca17e..c050b09345a0 100644
--- a/ipc/ipdl/ipdl/type.py
+++ b/ipc/ipdl/ipdl/type.py
@@ -15,10 +15,6 @@ from ipdl.ast import priorityList
 import ipdl.builtin as builtin
 from ipdl.util import hash_str
 
-# Used to get the list of Gecko process types
-# xpcom/geckoprocesstypes_generator/geckoprocesstypes/__init__.py
-import geckoprocesstypes
-
 _DELETE_MSG = "__delete__"
 
 
@@ -985,13 +981,6 @@ class GatherDecls(TcheckVisitor):
 
             p = tu.protocol
 
-            proc_options = [
-                "any",
-                "anychild",  # non-Parent process
-                "anydom",  # Parent or Content process
-                "compositor",  # Parent or GPU process
-            ] + [p.proc_typename for p in geckoprocesstypes.process_types]
-
             self.checkAttributes(
                 p.attributes,
                 {
@@ -1000,8 +989,6 @@ class GatherDecls(TcheckVisitor):
                     "NeedsOtherPid": None,
                     "ChildImpl": ("virtual", StringLiteral),
                     "ParentImpl": ("virtual", StringLiteral),
-                    "ChildProc": proc_options,
-                    "ParentProc": proc_options,
                 },
             )
 
@@ -1288,12 +1275,8 @@ class GatherDecls(TcheckVisitor):
         if not p.decl.type.isToplevel() and p.decl.type.needsotherpid:
             self.error(p.loc, "[NeedsOtherPid] only applies to toplevel protocols")
 
-        if p.decl.type.isToplevel():
-            if not p.decl.type.isRefcounted():
-                self.error(p.loc, "Toplevel protocols cannot be [ManualDealloc]")
-
-            if "ChildProc" not in p.attributes:
-                self.error(p.loc, "Toplevel protocols must specify [ChildProc]")
+        if p.decl.type.isToplevel() and not p.decl.type.isRefcounted():
+            self.error(p.loc, "Toplevel protocols cannot be [ManualDealloc]")
 
         # FIXME/cjones declare all the little C++ thingies that will
         # be generated.  they're not relevant to IPDL itself, but
diff --git a/ipc/ipdl/test/gtest/PIPDLUnitTest.ipdl b/ipc/ipdl/test/gtest/PIPDLUnitTest.ipdl
index 6bc5693a721c..2f06bccac8d0 100644
--- a/ipc/ipdl/test/gtest/PIPDLUnitTest.ipdl
+++ b/ipc/ipdl/test/gtest/PIPDLUnitTest.ipdl
@@ -20,8 +20,7 @@ struct TestPartResult {
 };
 
 // Primary actor for the IPDLUnitTest process and thread.
-[NeedsOtherPid, ChildProc=any]
-async protocol PIPDLUnitTest {
+[NeedsOtherPid] async protocol PIPDLUnitTest {
  child:
   async Start(nsCString name, ScopedPort port, nsID channelId);
 
diff --git a/ipc/ipdl/test/gtest/PTestBasic.ipdl b/ipc/ipdl/test/gtest/PTestBasic.ipdl
index 9bc81f48307c..25f32cacbdef 100644
--- a/ipc/ipdl/test/gtest/PTestBasic.ipdl
+++ b/ipc/ipdl/test/gtest/PTestBasic.ipdl
@@ -5,7 +5,6 @@
 namespace mozilla {
 namespace _ipdltest {
 
-[ChildProc=any]
 async protocol PTestBasic {
 child:
     async Hello();
diff --git a/ipc/ipdl/test/gtest/PTestCrossProcessSemaphore.ipdl b/ipc/ipdl/test/gtest/PTestCrossProcessSemaphore.ipdl
index fd25afbd13a1..65609e402912 100644
--- a/ipc/ipdl/test/gtest/PTestCrossProcessSemaphore.ipdl
+++ b/ipc/ipdl/test/gtest/PTestCrossProcessSemaphore.ipdl
@@ -7,7 +7,7 @@
 namespace mozilla {
 namespace _ipdltest {
 
-[ParentImpl=virtual, ChildImpl=virtual, ChildProc=any]
+[ParentImpl=virtual, ChildImpl=virtual]
 async protocol PTestCrossProcessSemaphore {
 child:
     async CrossProcessSemaphore(CrossProcessSemaphoreHandle aSem);
diff --git a/ipc/ipdl/test/gtest/PTestInduceConnectionError.ipdl b/ipc/ipdl/test/gtest/PTestInduceConnectionError.ipdl
index d5de8938842b..82069b2ac36c 100644
--- a/ipc/ipdl/test/gtest/PTestInduceConnectionError.ipdl
+++ b/ipc/ipdl/test/gtest/PTestInduceConnectionError.ipdl
@@ -5,7 +5,7 @@
 namespace mozilla {
 namespace _ipdltest {
 
-[ParentImpl=virtual, ChildImpl=virtual, ChildProc=any]
+[ParentImpl=virtual, ChildImpl=virtual]
 async protocol PTestInduceConnectionError {
 child:
     async Begin();
diff --git a/ipc/ipdl/test/gtest/PTestManyHandles.ipdl b/ipc/ipdl/test/gtest/PTestManyHandles.ipdl
index 31e03cee6f74..b1db633fdb10 100644
--- a/ipc/ipdl/test/gtest/PTestManyHandles.ipdl
+++ b/ipc/ipdl/test/gtest/PTestManyHandles.ipdl
@@ -5,7 +5,7 @@
 namespace mozilla {
 namespace _ipdltest {
 
-[ParentImpl=virtual, ChildImpl=virtual, ChildProc=any]
+[ParentImpl=virtual, ChildImpl=virtual]
 async protocol PTestManyHandles {
 child:
     async ManyHandles(FileDescriptor[] descrs);
diff --git a/ipc/ipdl/test/ipdl/error/AsyncCtorReturns.ipdl b/ipc/ipdl/test/ipdl/error/AsyncCtorReturns.ipdl
index 8295a1c9a709..831d4d1159aa 100644
--- a/ipc/ipdl/test/ipdl/error/AsyncCtorReturns.ipdl
+++ b/ipc/ipdl/test/ipdl/error/AsyncCtorReturns.ipdl
@@ -2,7 +2,6 @@
 
 include protocol AsyncCtorReturnsManagee;
 
-[ChildProc=any]
 protocol AsyncCtorReturns {
   manages AsyncCtorReturnsManagee;
 
diff --git a/ipc/ipdl/test/ipdl/error/AsyncCtorReturnsManagee.ipdl b/ipc/ipdl/test/ipdl/error/AsyncCtorReturnsManagee.ipdl
index 46aeb6e9fddb..f38e2bd0ea21 100644
--- a/ipc/ipdl/test/ipdl/error/AsyncCtorReturnsManagee.ipdl
+++ b/ipc/ipdl/test/ipdl/error/AsyncCtorReturnsManagee.ipdl
@@ -2,7 +2,6 @@
 
 include protocol AsyncCtorReturns;
 
-[ChildProc=any]
 protocol AsyncCtorReturnsManagee {
   manager AsyncCtorReturns;
 
diff --git a/ipc/ipdl/test/ipdl/error/AsyncInsideSync.ipdl b/ipc/ipdl/test/ipdl/error/AsyncInsideSync.ipdl
index 104ced1c72d6..d2fa481e7f02 100644
--- a/ipc/ipdl/test/ipdl/error/AsyncInsideSync.ipdl
+++ b/ipc/ipdl/test/ipdl/error/AsyncInsideSync.ipdl
@@ -3,7 +3,6 @@
 //error: inside_sync nested messages must be sync (here, message `Msg' in protocol `AsyncInsideSync')
 //error: message `Msg' requires more powerful send semantics than its protocol `AsyncInsideSync' provides
 
-[ChildProc=any]
 protocol AsyncInsideSync {
 child:
     [Nested=inside_sync] async Msg();
diff --git a/ipc/ipdl/test/ipdl/error/ExtendedAttrInvalidNestedValue.ipdl b/ipc/ipdl/test/ipdl/error/ExtendedAttrInvalidNestedValue.ipdl
index 64899286dbc7..e58d5d553343 100644
--- a/ipc/ipdl/test/ipdl/error/ExtendedAttrInvalidNestedValue.ipdl
+++ b/ipc/ipdl/test/ipdl/error/ExtendedAttrInvalidNestedValue.ipdl
@@ -1,6 +1,5 @@
 //error: invalid value for attribute `Nested', expected one of: not, inside_sync, inside_cpow
 
-[ChildProc=any]
 protocol ExtendedAttrInvalidNestedValue {
 child:
   [Nested=invalid] async __delete__();
diff --git a/ipc/ipdl/test/ipdl/error/ExtendedAttrInvalidPriorityValue.ipdl b/ipc/ipdl/test/ipdl/error/ExtendedAttrInvalidPriorityValue.ipdl
index 51f21f045873..7625a85e130b 100644
--- a/ipc/ipdl/test/ipdl/error/ExtendedAttrInvalidPriorityValue.ipdl
+++ b/ipc/ipdl/test/ipdl/error/ExtendedAttrInvalidPriorityValue.ipdl
@@ -1,6 +1,5 @@
 //error: invalid value for attribute `Priority', expected one of: normal, input, vsync, mediumhigh, control
 
-[ChildProc=any]
 protocol ExtendedAttrInvalidPriorityValue {
 child:
   [Priority=invalid] async __delete__();
diff --git a/ipc/ipdl/test/ipdl/error/ForgottenManager.ipdl b/ipc/ipdl/test/ipdl/error/ForgottenManager.ipdl
index f2c524056a83..4335dc8dc771 100644
--- a/ipc/ipdl/test/ipdl/error/ForgottenManager.ipdl
+++ b/ipc/ipdl/test/ipdl/error/ForgottenManager.ipdl
@@ -4,7 +4,6 @@ include protocol ManageeForgot;
 
 // ManageeForgot should have this protocol as its manager.
 
-[ChildProc=any]
 protocol ForgottenManager {
     manages ManageeForgot;
 child:
diff --git a/ipc/ipdl/test/ipdl/error/InsideCpowToChild.ipdl b/ipc/ipdl/test/ipdl/error/InsideCpowToChild.ipdl
index 054964a817ed..4338555952e5 100644
--- a/ipc/ipdl/test/ipdl/error/InsideCpowToChild.ipdl
+++ b/ipc/ipdl/test/ipdl/error/InsideCpowToChild.ipdl
@@ -3,7 +3,6 @@
 //error: inside_cpow nested parent-to-child messages are verboten (here, message `Msg' in protocol `InsideCpowToChild')
 //error: message `Msg' requires more powerful send semantics than its protocol `InsideCpowToChild' provides
 
-[ChildProc=any]
 protocol InsideCpowToChild {
 child:
     [Nested=inside_cpow] sync Msg();
diff --git a/ipc/ipdl/test/ipdl/error/IntrAsyncManager.ipdl b/ipc/ipdl/test/ipdl/error/IntrAsyncManager.ipdl
index dc5768df28bf..7bf413ef6163 100644
--- a/ipc/ipdl/test/ipdl/error/IntrAsyncManager.ipdl
+++ b/ipc/ipdl/test/ipdl/error/IntrAsyncManager.ipdl
@@ -2,7 +2,6 @@
 
 include protocol IntrAsyncManagee;
 
-[ChildProc=any]
 async protocol IntrAsyncManager {
     manages IntrAsyncManagee;
 parent:
diff --git a/ipc/ipdl/test/ipdl/error/IntrSyncManager.ipdl b/ipc/ipdl/test/ipdl/error/IntrSyncManager.ipdl
index f8e762093c95..80a82ab6d805 100644
--- a/ipc/ipdl/test/ipdl/error/IntrSyncManager.ipdl
+++ b/ipc/ipdl/test/ipdl/error/IntrSyncManager.ipdl
@@ -2,7 +2,6 @@
 
 include protocol IntrSyncManagee;
 
-[ChildProc=any]
 sync protocol IntrSyncManager {
     manages IntrSyncManagee;
 parent:
diff --git a/ipc/ipdl/test/ipdl/error/ManageeForgot.ipdl b/ipc/ipdl/test/ipdl/error/ManageeForgot.ipdl
index 9e11fe49fdd5..babe2f065816 100644
--- a/ipc/ipdl/test/ipdl/error/ManageeForgot.ipdl
+++ b/ipc/ipdl/test/ipdl/error/ManageeForgot.ipdl
@@ -5,7 +5,6 @@ include protocol ForgottenManager;
 // See ForgottenManager. This includes ForgottenManager to ensure that
 // loading this file fails.
 
-[ChildProc=any]
 protocol ManageeForgot {
 child:
     async __delete__();
diff --git a/ipc/ipdl/test/ipdl/error/ManagerForgot.ipdl b/ipc/ipdl/test/ipdl/error/ManagerForgot.ipdl
index ae87534fb9ad..00c08ebe87ad 100644
--- a/ipc/ipdl/test/ipdl/error/ManagerForgot.ipdl
+++ b/ipc/ipdl/test/ipdl/error/ManagerForgot.ipdl
@@ -5,7 +5,6 @@ include protocol ForgottenManagee;
 // See ForgottenManagee.ipdl. This includes ForgottenManagee to
 // ensure that loading this file fails.
 
-[ChildProc=any]
 protocol ManagerForgot {
 child:
     async Msg();
diff --git a/ipc/ipdl/test/ipdl/error/Nullable.ipdl b/ipc/ipdl/test/ipdl/error/Nullable.ipdl
index c5257accbbaa..7761f7364652 100644
--- a/ipc/ipdl/test/ipdl/error/Nullable.ipdl
+++ b/ipc/ipdl/test/ipdl/error/Nullable.ipdl
@@ -1,6 +1,5 @@
 //error: `nullable' qualifier for type `int' is unsupported
 
-[ChildProc=any]
 protocol PNullable {
 child:
     async Msg(nullable int i);
diff --git a/ipc/ipdl/test/ipdl/error/Nullable2.ipdl b/ipc/ipdl/test/ipdl/error/Nullable2.ipdl
index 3dcd66a32179..8248b7cb7c0d 100644
--- a/ipc/ipdl/test/ipdl/error/Nullable2.ipdl
+++ b/ipc/ipdl/test/ipdl/error/Nullable2.ipdl
@@ -4,7 +4,6 @@ union Union {
     nullable int;
 };
 
-[ChildProc=any]
 protocol Nullable2 {
 child:
     async Msg(Union i);
diff --git a/ipc/ipdl/test/ipdl/error/PBadArrayBase.ipdl b/ipc/ipdl/test/ipdl/error/PBadArrayBase.ipdl
index 3d791761c27b..4afdcb4c8e11 100644
--- a/ipc/ipdl/test/ipdl/error/PBadArrayBase.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PBadArrayBase.ipdl
@@ -1,6 +1,5 @@
 //error: argument typename `X' of message `Test' has not been declared
 
-[ChildProc=any]
 protocol PBadArrayBase {
 child:
   async Test(X[] x);
diff --git a/ipc/ipdl/test/ipdl/error/PBadNestedManagee.ipdl b/ipc/ipdl/test/ipdl/error/PBadNestedManagee.ipdl
index 3fda3666740d..eca24e00d4b2 100644
--- a/ipc/ipdl/test/ipdl/error/PBadNestedManagee.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PBadNestedManagee.ipdl
@@ -2,8 +2,7 @@
 
 include protocol PBadNestedManager;
 
-[NestedUpTo=inside_sync, ChildProc=any]
-async protocol PBadNestedManagee {
+[NestedUpTo=inside_sync] async protocol PBadNestedManagee {
     manager PBadNestedManager;
 child:
     async __delete__();
diff --git a/ipc/ipdl/test/ipdl/error/PBadNestedManager.ipdl b/ipc/ipdl/test/ipdl/error/PBadNestedManager.ipdl
index b395da2f30a1..9fc744f13a1b 100644
--- a/ipc/ipdl/test/ipdl/error/PBadNestedManager.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PBadNestedManager.ipdl
@@ -2,8 +2,7 @@
 
 include protocol PBadNestedManagee;
 
-[NestedUpTo=not, ChildProc=any]
-async protocol PBadNestedManager {
+[NestedUpTo=not] async protocol PBadNestedManager {
     manages PBadNestedManagee;
 parent:
     async PBadNestedManagee();
diff --git a/ipc/ipdl/test/ipdl/error/PBadSideImpl.ipdl b/ipc/ipdl/test/ipdl/error/PBadSideImpl.ipdl
index 787bba1d04d4..75aebd46705c 100644
--- a/ipc/ipdl/test/ipdl/error/PBadSideImpl.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PBadSideImpl.ipdl
@@ -1,7 +1,7 @@
 //error: invalid value for attribute `ParentImpl', expected one of: virtual, StringLiteral
 //error: invalid value for attribute `ChildImpl', expected one of: virtual, StringLiteral
 
-[ParentImpl=NotQuoted, ChildImpl, ChildProc=any]
+[ParentImpl=NotQuoted, ChildImpl]
 async protocol PBadSideImpl {
  parent:
   async __delete__();
diff --git a/ipc/ipdl/test/ipdl/error/PBadUniquePtrBase.ipdl b/ipc/ipdl/test/ipdl/error/PBadUniquePtrBase.ipdl
index 8058fb533478..b93b20742d8f 100644
--- a/ipc/ipdl/test/ipdl/error/PBadUniquePtrBase.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PBadUniquePtrBase.ipdl
@@ -1,6 +1,5 @@
 //error: argument typename `UndeclaredType' of message `Test' has not been declared
 
-[ChildProc=any]
 protocol PBadUniquePtrBase {
 child:
   async Test(UniquePtr<UndeclaredType> x);
diff --git a/ipc/ipdl/test/ipdl/error/PCompressInvalid.ipdl b/ipc/ipdl/test/ipdl/error/PCompressInvalid.ipdl
index bc81e4544b24..5ceaaad9acf0 100644
--- a/ipc/ipdl/test/ipdl/error/PCompressInvalid.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PCompressInvalid.ipdl
@@ -2,7 +2,6 @@
 
 include protocol compressCtor;
 
-[ChildProc=any]
 async protocol PCompressInvalid {
 child:
     [Compress=Invalid] async Message();
diff --git a/ipc/ipdl/test/ipdl/error/PDouble.ipdl b/ipc/ipdl/test/ipdl/error/PDouble.ipdl
index a6c6dd3a8d89..e08ff1d063b7 100644
--- a/ipc/ipdl/test/ipdl/error/PDouble.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PDouble.ipdl
@@ -6,7 +6,6 @@
 // obviously bad.
 include protocol PDouble;
 
-[ChildProc=any]
 protocol PDouble {
 child: async Msg();
 };
diff --git a/ipc/ipdl/test/ipdl/error/PExtendedAttrInvalidValue.ipdl b/ipc/ipdl/test/ipdl/error/PExtendedAttrInvalidValue.ipdl
index 796f25d8c2e5..9720acdd4177 100644
--- a/ipc/ipdl/test/ipdl/error/PExtendedAttrInvalidValue.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PExtendedAttrInvalidValue.ipdl
@@ -1,7 +1,6 @@
 //error: invalid value for attribute `NestedUpTo', expected one of: not, inside_sync, inside_cpow
 
-[NestedUpTo=invalid, ChildProc=any]
-async protocol PExtendedAttrInvalidValue {
+[NestedUpTo=invalid] async protocol PExtendedAttrInvalidValue {
 parent:
     async Msg();
 };
diff --git a/ipc/ipdl/test/ipdl/error/PExtendedAttrRepeated.ipdl b/ipc/ipdl/test/ipdl/error/PExtendedAttrRepeated.ipdl
index c15dbce788c3..e33411a8771b 100644
--- a/ipc/ipdl/test/ipdl/error/PExtendedAttrRepeated.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PExtendedAttrRepeated.ipdl
@@ -1,7 +1,6 @@
 //error: Repeated extended attribute `RefCounted'
 
-[RefCounted, RefCounted, ChildProc=any]
-async protocol PExtendedAttrRepeated {
+[RefCounted, RefCounted] async protocol PExtendedAttrRepeated {
 parent:
     async Msg();
 };
diff --git a/ipc/ipdl/test/ipdl/error/PExtendedAttrUnexpectedValue.ipdl b/ipc/ipdl/test/ipdl/error/PExtendedAttrUnexpectedValue.ipdl
index dcc7b043c5e7..de1d81c0eb82 100644
--- a/ipc/ipdl/test/ipdl/error/PExtendedAttrUnexpectedValue.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PExtendedAttrUnexpectedValue.ipdl
@@ -1,7 +1,6 @@
 //error: unexpected value for valueless attribute `ManualDealloc'
 
-[ManualDealloc=invalid, ChildProc=any]
-async protocol PExtendedAttrUnexpectedValue {
+[ManualDealloc=invalid] async protocol PExtendedAttrUnexpectedValue {
 parent:
     async Msg();
 };
diff --git a/ipc/ipdl/test/ipdl/error/PExtendedAttrUnknownAttribute.ipdl b/ipc/ipdl/test/ipdl/error/PExtendedAttrUnknownAttribute.ipdl
index 193c1d660842..414763efdd61 100644
--- a/ipc/ipdl/test/ipdl/error/PExtendedAttrUnknownAttribute.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PExtendedAttrUnknownAttribute.ipdl
@@ -1,7 +1,6 @@
 //error: unknown attribute `InvalidAttr'
 
-[InvalidAttr, ChildProc=any]
-async protocol PExtendedAttrUnknownValue {
+[InvalidAttr] async protocol PExtendedAttrUnknownValue {
 parent:
     async Msg();
 };
diff --git a/ipc/ipdl/test/ipdl/error/PInconsistentMoveOnly.ipdl b/ipc/ipdl/test/ipdl/error/PInconsistentMoveOnly.ipdl
index 9968b3b2ab7d..4e88a82050be 100644
--- a/ipc/ipdl/test/ipdl/error/PInconsistentMoveOnly.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PInconsistentMoveOnly.ipdl
@@ -7,7 +7,6 @@ using class mozilla::ipc::SomeMoveonlyType from "SomeFile.h";
 [MoveOnly=send] using class mozilla::ipc::SomeMoveonlySendType from "SomeFile.h";
 [MoveOnly=data] using class mozilla::ipc::SomeMoveonlySendType from "SomeFile.h";
 
-[ChildProc=any]
 protocol PInconsistentMoveOnly {
 child:
   async SomeMessage();
diff --git a/ipc/ipdl/test/ipdl/error/PIntrNested.ipdl b/ipc/ipdl/test/ipdl/error/PIntrNested.ipdl
index c487bcd49d8f..948cdc111837 100644
--- a/ipc/ipdl/test/ipdl/error/PIntrNested.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PIntrNested.ipdl
@@ -1,6 +1,5 @@
 //error: intr message `Msg' cannot specify [Nested]
 
-[ChildProc=any]
 intr protocol PIntrNested {
 child:
   [Nested=inside_sync, LegacyIntr] intr Msg();
diff --git a/ipc/ipdl/test/ipdl/error/PIntrNestedProtocol.ipdl b/ipc/ipdl/test/ipdl/error/PIntrNestedProtocol.ipdl
index dd95a7c00252..4267bf7a847a 100644
--- a/ipc/ipdl/test/ipdl/error/PIntrNestedProtocol.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PIntrNestedProtocol.ipdl
@@ -1,7 +1,6 @@
 //error: intr protocol `PIntrNestedProtocol' cannot specify [NestedUpTo]
 
-[NestedUpTo=inside_sync, ChildProc=any]
-intr protocol PIntrNestedProtocol {
+[NestedUpTo=inside_sync] intr protocol PIntrNestedProtocol {
 child:
   [LegacyIntr] intr Msg();
 };
diff --git a/ipc/ipdl/test/ipdl/error/PIntrPriority.ipdl b/ipc/ipdl/test/ipdl/error/PIntrPriority.ipdl
index c8bf75e9a301..5bc539983aca 100644
--- a/ipc/ipdl/test/ipdl/error/PIntrPriority.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PIntrPriority.ipdl
@@ -1,6 +1,5 @@
 //error: intr message `Msg' cannot specify [Priority]
 
-[ChildProc=any]
 intr protocol PIntrPriority {
 child:
   [Priority=vsync, LegacyIntr] intr Msg();
diff --git a/ipc/ipdl/test/ipdl/error/PLazySendInvalid.ipdl b/ipc/ipdl/test/ipdl/error/PLazySendInvalid.ipdl
index b34f68613258..282a007addc0 100644
--- a/ipc/ipdl/test/ipdl/error/PLazySendInvalid.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PLazySendInvalid.ipdl
@@ -1,6 +1,5 @@
 //error: unexpected value for valueless attribute `LazySend'
 
-[ChildProc=any]
 async protocol PLazySendInvalid {
 child:
     [LazySend=Invalid] async Message();
diff --git a/ipc/ipdl/test/ipdl/error/PLazySendSync.ipdl b/ipc/ipdl/test/ipdl/error/PLazySendSync.ipdl
index 76e9e60fb935..308b734fe539 100644
--- a/ipc/ipdl/test/ipdl/error/PLazySendSync.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PLazySendSync.ipdl
@@ -1,6 +1,5 @@
 //error: non-async message `Message' cannot specify [LazySend]
 
-[ChildProc=any]
 sync protocol PLazySendSync {
 child:
     [LazySend] sync Message() returns (bool ok);
diff --git a/ipc/ipdl/test/ipdl/error/PMissingProc.ipdl b/ipc/ipdl/test/ipdl/error/PMissingProc.ipdl
deleted file mode 100644
index b4d32e55acf1..000000000000
--- a/ipc/ipdl/test/ipdl/error/PMissingProc.ipdl
+++ /dev/null
@@ -1,6 +0,0 @@
-//error: Toplevel protocols must specify [ChildProc]
-
-protocol PMissingProc {
-parent:
-    async Msg();
-};
diff --git a/ipc/ipdl/test/ipdl/error/PNoTaintWithoutTainted.ipdl b/ipc/ipdl/test/ipdl/error/PNoTaintWithoutTainted.ipdl
index b196050c48f7..cfdde1f02c67 100644
--- a/ipc/ipdl/test/ipdl/error/PNoTaintWithoutTainted.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PNoTaintWithoutTainted.ipdl
@@ -1,6 +1,5 @@
 //error: argument typename `int' of message `foo' has a NoTaint attribute, but the message lacks the Tainted attribute
 
-[ChildProc=any]
 intr protocol PNoTaintWithoutTainted {
 child:
     async foo([NoTaint=passback] int id);
diff --git a/ipc/ipdl/test/ipdl/error/PToplevelManualDealloc.ipdl b/ipc/ipdl/test/ipdl/error/PToplevelManualDealloc.ipdl
index 1936fda2bbe1..97822b65bd68 100644
--- a/ipc/ipdl/test/ipdl/error/PToplevelManualDealloc.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PToplevelManualDealloc.ipdl
@@ -1,7 +1,6 @@
 //error: Toplevel protocols cannot be [ManualDealloc]
 
-[ManualDealloc, ChildProc=any]
-async protocol PToplevelManualDealloc {
+[ManualDealloc] async protocol PToplevelManualDealloc {
 child:
     async __delete__();
 };
diff --git a/ipc/ipdl/test/ipdl/error/PUniquePtrRecursive.ipdl b/ipc/ipdl/test/ipdl/error/PUniquePtrRecursive.ipdl
index 98992f700eb0..83c9459ec6d0 100644
--- a/ipc/ipdl/test/ipdl/error/PUniquePtrRecursive.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PUniquePtrRecursive.ipdl
@@ -1,6 +1,5 @@
 //error: bad syntax near `UniquePtr'
 
-[ChildProc=any]
 protocol PUniquePtrRecursive {
 child: async Msg( UniquePtr< UniquePtr<int> > aa);
 };
diff --git a/ipc/ipdl/test/ipdl/error/PUniquePtrSelfRecStruct.ipdl b/ipc/ipdl/test/ipdl/error/PUniquePtrSelfRecStruct.ipdl
index a0fb3b91c08d..c9a54b22b26f 100644
--- a/ipc/ipdl/test/ipdl/error/PUniquePtrSelfRecStruct.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PUniquePtrSelfRecStruct.ipdl
@@ -4,7 +4,6 @@ struct X {
     UniquePtr<X> x;
 };
 
-[ChildProc=any]
 protocol PUniquePtrSelfRecStruct {
 child: async Msg(UniquePtr<X> aa);
 };
diff --git a/ipc/ipdl/test/ipdl/error/PUniquePtrSelfRecUnion.ipdl b/ipc/ipdl/test/ipdl/error/PUniquePtrSelfRecUnion.ipdl
index 396ffef0e243..5dba38263fea 100644
--- a/ipc/ipdl/test/ipdl/error/PUniquePtrSelfRecUnion.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PUniquePtrSelfRecUnion.ipdl
@@ -2,7 +2,6 @@
 
 union X { UniquePtr<X>; };
 
-[ChildProc=any]
 protocol PUniquePtrSelfRecUnion {
 child: async Msg(UniquePtr<X> aa);
 };
diff --git a/ipc/ipdl/test/ipdl/error/PUnknownProc.ipdl b/ipc/ipdl/test/ipdl/error/PUnknownProc.ipdl
deleted file mode 100644
index 0ec4e3f3c73a..000000000000
--- a/ipc/ipdl/test/ipdl/error/PUnknownProc.ipdl
+++ /dev/null
@@ -1,7 +0,0 @@
-//error: invalid value for attribute `ChildProc', expected one of: any, anychild, anydom, compositor, Parent, Content, IPDLUnitTest, GMPlugin, GPU, VR, RDD, Socket, RemoteSandboxBroker, ForkServer, Utility
-
-[ChildProc=unknowntype]
-protocol PUnknownProc {
-parent:
-    async Msg();
-};
diff --git a/ipc/ipdl/test/ipdl/error/PasyncMessageListed.ipdl b/ipc/ipdl/test/ipdl/error/PasyncMessageListed.ipdl
index 18d6e85ea4f6..6a3cdad0eef3 100644
--- a/ipc/ipdl/test/ipdl/error/PasyncMessageListed.ipdl
+++ b/ipc/ipdl/test/ipdl/error/PasyncMessageListed.ipdl
@@ -1,6 +1,5 @@
 //error: IPC message PasyncMessageListed::Msg is async, can be delisted
 
-[ChildProc=any]
 protocol PasyncMessageListed {
 parent:
     async Msg();
diff --git a/ipc/ipdl/test/ipdl/error/ReplyPrioWithoutReturns.ipdl b/ipc/ipdl/test/ipdl/error/ReplyPrioWithoutReturns.ipdl
index be499f6d4c03..0d1cd5121753 100644
--- a/ipc/ipdl/test/ipdl/error/ReplyPrioWithoutReturns.ipdl
+++ b/ipc/ipdl/test/ipdl/error/ReplyPrioWithoutReturns.ipdl
@@ -1,6 +1,4 @@
 //error: non-returns message `NormalPrio' cannot specify [ReplyPriority]
-
-[ChildProc=any]
 async protocol ReplyPrioWithoutReturns
 {
 child:
diff --git a/ipc/ipdl/test/ipdl/error/SyncAsyncManagee.ipdl b/ipc/ipdl/test/ipdl/error/SyncAsyncManagee.ipdl
index e011e90d799c..166881ae1e3b 100644
--- a/ipc/ipdl/test/ipdl/error/SyncAsyncManagee.ipdl
+++ b/ipc/ipdl/test/ipdl/error/SyncAsyncManagee.ipdl
@@ -2,7 +2,6 @@
 
 include protocol SyncAsyncManager;
 
-[ChildProc=any]
 sync protocol SyncAsyncManagee {
     manager SyncAsyncManager;
 child:
diff --git a/ipc/ipdl/test/ipdl/error/SyncAsyncManager.ipdl b/ipc/ipdl/test/ipdl/error/SyncAsyncManager.ipdl
index f189df1cbd1e..9dbc7a6318f7 100644
--- a/ipc/ipdl/test/ipdl/error/SyncAsyncManager.ipdl
+++ b/ipc/ipdl/test/ipdl/error/SyncAsyncManager.ipdl
@@ -2,7 +2,6 @@
 
 include protocol SyncAsyncManagee;
 
-[ChildProc=any]
 async protocol SyncAsyncManager {
     manages SyncAsyncManagee;
 parent:
diff --git a/ipc/ipdl/test/ipdl/error/SyncPrio.ipdl b/ipc/ipdl/test/ipdl/error/SyncPrio.ipdl
index 73c0cdfd44ce..cbf833b6205a 100644
--- a/ipc/ipdl/test/ipdl/error/SyncPrio.ipdl
+++ b/ipc/ipdl/test/ipdl/error/SyncPrio.ipdl
@@ -1,6 +1,4 @@
 //error: non-async message `NormalPrio' cannot specify [ReplyPriority]
-
-[ChildProc=any]
 sync protocol SyncPrio
 {
 child:
diff --git a/ipc/ipdl/test/ipdl/error/array_Recursive.ipdl b/ipc/ipdl/test/ipdl/error/array_Recursive.ipdl
index d89d4b3cad37..f5027e229996 100644
--- a/ipc/ipdl/test/ipdl/error/array_Recursive.ipdl
+++ b/ipc/ipdl/test/ipdl/error/array_Recursive.ipdl
@@ -1,6 +1,5 @@
 //error: bad syntax near `['
 
-[ChildProc=any]
 protocol array_Recursive {
 child: async Msg(int[][] aa);
 };
diff --git a/ipc/ipdl/test/ipdl/error/badProtocolInclude.ipdl b/ipc/ipdl/test/ipdl/error/badProtocolInclude.ipdl
index 4ff6db26597d..3f82bef9b2ad 100644
--- a/ipc/ipdl/test/ipdl/error/badProtocolInclude.ipdl
+++ b/ipc/ipdl/test/ipdl/error/badProtocolInclude.ipdl
@@ -4,7 +4,6 @@ include protocol IDONTEXIST;
 
 // error: nonexistent protocol ^^^
 
-[ChildProc=any]
 protocol badProtocolInclude {
 child: async Msg();
 };
diff --git a/ipc/ipdl/test/ipdl/error/compressCtor.ipdl b/ipc/ipdl/test/ipdl/error/compressCtor.ipdl
index 93c300333dcf..9db05d495d36 100644
--- a/ipc/ipdl/test/ipdl/error/compressCtor.ipdl
+++ b/ipc/ipdl/test/ipdl/error/compressCtor.ipdl
@@ -3,7 +3,6 @@
 
 include protocol compressCtorManagee;
 
-[ChildProc=any]
 intr protocol compressCtor {
     manages compressCtorManagee;
 
diff --git a/ipc/ipdl/test/ipdl/error/conflictProtocolMsg.ipdl b/ipc/ipdl/test/ipdl/error/conflictProtocolMsg.ipdl
index 4756e0c032d5..b223dab78371 100644
--- a/ipc/ipdl/test/ipdl/error/conflictProtocolMsg.ipdl
+++ b/ipc/ipdl/test/ipdl/error/conflictProtocolMsg.ipdl
@@ -1,6 +1,5 @@
 //error: ctor for protocol `conflictProtocolMsg', which is not managed by protocol `conflictProtocolMsg'
 
-[ChildProc=any]
 protocol conflictProtocolMsg {
 
     // it's an error to re-use the protocol name as a message ID; these
diff --git a/ipc/ipdl/test/ipdl/error/cyclecheck_Parent.ipdl b/ipc/ipdl/test/ipdl/error/cyclecheck_Parent.ipdl
index 7b3a135518ed..f2eb0606411f 100644
--- a/ipc/ipdl/test/ipdl/error/cyclecheck_Parent.ipdl
+++ b/ipc/ipdl/test/ipdl/error/cyclecheck_Parent.ipdl
@@ -2,7 +2,6 @@
 
 include protocol cyclecheck_Child;
 
-[ChildProc=any]
 protocol cyclecheck_Parent {
     manages cyclecheck_Child;
 
diff --git a/ipc/ipdl/test/ipdl/error/dtorReserved.ipdl b/ipc/ipdl/test/ipdl/error/dtorReserved.ipdl
index ac5d37c7b6cd..51833489be2c 100644
--- a/ipc/ipdl/test/ipdl/error/dtorReserved.ipdl
+++ b/ipc/ipdl/test/ipdl/error/dtorReserved.ipdl
@@ -1,6 +1,5 @@
 //error: lexically invalid characters `~SomeMsg();
 
-[ChildProc=any]
 protocol dtorReserved {
 
     // it's an error to use old-style dtor syntax
diff --git a/ipc/ipdl/test/ipdl/error/inconsistentRC.ipdl b/ipc/ipdl/test/ipdl/error/inconsistentRC.ipdl
index a00bca66e434..ee1375c31213 100644
--- a/ipc/ipdl/test/ipdl/error/inconsistentRC.ipdl
+++ b/ipc/ipdl/test/ipdl/error/inconsistentRC.ipdl
@@ -3,7 +3,6 @@
 [RefCounted] using class mozilla::ipc::SomeRefcountedType from "SomeFile.h";
 using class mozilla::ipc::SomeRefcountedType from "SomeFile.h";
 
-[ChildProc=any]
 protocol inconsistentRC {
 child:
   async SomeMessage();
diff --git a/ipc/ipdl/test/ipdl/error/intrMessageCompress.ipdl b/ipc/ipdl/test/ipdl/error/intrMessageCompress.ipdl
index e56cfc5d8ce1..49bd5d472119 100644
--- a/ipc/ipdl/test/ipdl/error/intrMessageCompress.ipdl
+++ b/ipc/ipdl/test/ipdl/error/intrMessageCompress.ipdl
@@ -1,7 +1,6 @@
 //error: message `foo' in protocol `intrMessageCompress' requests compression but is not async
 //error: message `bar' in protocol `intrMessageCompress' requests compression but is not async
 
-[ChildProc=any]
 intr protocol intrMessageCompress {
 parent:
     [Compress, LegacyIntr] intr foo();
diff --git a/ipc/ipdl/test/ipdl/error/maybe_Recursive.ipdl b/ipc/ipdl/test/ipdl/error/maybe_Recursive.ipdl
index 2f356b423aa5..b03992419988 100644
--- a/ipc/ipdl/test/ipdl/error/maybe_Recursive.ipdl
+++ b/ipc/ipdl/test/ipdl/error/maybe_Recursive.ipdl
@@ -1,6 +1,5 @@
 //error: bad syntax near `?'
 
-[ChildProc=any]
 protocol maybe_Recursive {
 child: async Msg(int?? aa);
 };
diff --git a/ipc/ipdl/test/ipdl/error/maybe_SelfRecStruct.ipdl b/ipc/ipdl/test/ipdl/error/maybe_SelfRecStruct.ipdl
index 9dff6a2152a0..a13cdc3647ee 100644
--- a/ipc/ipdl/test/ipdl/error/maybe_SelfRecStruct.ipdl
+++ b/ipc/ipdl/test/ipdl/error/maybe_SelfRecStruct.ipdl
@@ -4,7 +4,6 @@ struct X {
     X? x;
 };
 
-[ChildProc=any]
 protocol maybe_SelfRecStruct {
 child: async Msg(X? aa);
 };
diff --git a/ipc/ipdl/test/ipdl/error/maybe_SelfRecUnion.ipdl b/ipc/ipdl/test/ipdl/error/maybe_SelfRecUnion.ipdl
index b85497d9c127..3cd5cde22a66 100644
--- a/ipc/ipdl/test/ipdl/error/maybe_SelfRecUnion.ipdl
+++ b/ipc/ipdl/test/ipdl/error/maybe_SelfRecUnion.ipdl
@@ -2,7 +2,6 @@
 
 union X { X?; };
 
-[ChildProc=any]
 protocol maybe_SelfRecUnion {
 child: async Msg(X? aa);
 };
diff --git a/ipc/ipdl/test/ipdl/error/messageNoDirection.ipdl b/ipc/ipdl/test/ipdl/error/messageNoDirection.ipdl
index 5e889933cb5d..199bb089c3f1 100644
--- a/ipc/ipdl/test/ipdl/error/messageNoDirection.ipdl
+++ b/ipc/ipdl/test/ipdl/error/messageNoDirection.ipdl
@@ -1,6 +1,5 @@
 //error: missing message direction
 
-[ChildProc=any]
 protocol messageNoDirection {
     async NoDirection();
 };
diff --git a/ipc/ipdl/test/ipdl/error/multimanDupMgrsMgr.ipdl b/ipc/ipdl/test/ipdl/error/multimanDupMgrsMgr.ipdl
index 76e838cc57eb..ff96fe91a3d3 100644
--- a/ipc/ipdl/test/ipdl/error/multimanDupMgrsMgr.ipdl
+++ b/ipc/ipdl/test/ipdl/error/multimanDupMgrsMgr.ipdl
@@ -2,7 +2,6 @@
 
 include protocol multimanDupMgrs;
 
-[ChildProc=any]
 protocol multimanDupMgrsMgr {
     manages multimanDupMgrs;
 
diff --git a/ipc/ipdl/test/ipdl/error/mutualRecStruct.ipdl b/ipc/ipdl/test/ipdl/error/mutualRecStruct.ipdl
index 3224438e9002..9df16543bf86 100644
--- a/ipc/ipdl/test/ipdl/error/mutualRecStruct.ipdl
+++ b/ipc/ipdl/test/ipdl/error/mutualRecStruct.ipdl
@@ -17,7 +17,6 @@ struct Z {
     X x;
 };
 
-[ChildProc=any]
 protocol mutualRecStruct {
 child:
     async Test(X x, Y y, Z z);
diff --git a/ipc/ipdl/test/ipdl/error/mutualRecStructUnion.ipdl b/ipc/ipdl/test/ipdl/error/mutualRecStructUnion.ipdl
index 65345642a524..cd193f9f295e 100644
--- a/ipc/ipdl/test/ipdl/error/mutualRecStructUnion.ipdl
+++ b/ipc/ipdl/test/ipdl/error/mutualRecStructUnion.ipdl
@@ -17,7 +17,6 @@ struct Z {
     X x;
 };
 
-[ChildProc=any]
 protocol mutualRecStructUnion {
 child:
     async Test(X x, Y y, Z z);
diff --git a/ipc/ipdl/test/ipdl/error/noProtocolInHeader.ipdlh b/ipc/ipdl/test/ipdl/error/noProtocolInHeader.ipdlh
index 1997eb77d95b..8351adf4cc23 100644
--- a/ipc/ipdl/test/ipdl/error/noProtocolInHeader.ipdlh
+++ b/ipc/ipdl/test/ipdl/error/noProtocolInHeader.ipdlh
@@ -1,6 +1,5 @@
 //error: can't define a protocol in a header.  Do it in a protocol spec instead.
 
-[ChildProc=any]
 protocol noProtocolInHeader {
 child:
     async __delete__();
diff --git a/ipc/ipdl/test/ipdl/error/oldIncludeSyntax.ipdl b/ipc/ipdl/test/ipdl/error/oldIncludeSyntax.ipdl
index 6f90bc6d5f65..d13659a8e7c5 100644
--- a/ipc/ipdl/test/ipdl/error/oldIncludeSyntax.ipdl
+++ b/ipc/ipdl/test/ipdl/error/oldIncludeSyntax.ipdl
@@ -2,7 +2,6 @@
 
 include protocol "Foo.ipdl";
 
-[ChildProc=any]
 protocol oldIncludeSyntax {
 child: async __delete__(X x);
 };
diff --git a/ipc/ipdl/test/ipdl/error/redeclMessage.ipdl b/ipc/ipdl/test/ipdl/error/redeclMessage.ipdl
index 63a70d31a6e7..1247aa41cfc1 100644
--- a/ipc/ipdl/test/ipdl/error/redeclMessage.ipdl
+++ b/ipc/ipdl/test/ipdl/error/redeclMessage.ipdl
@@ -1,7 +1,6 @@
 //error: message name `Msg' already declared as `MessageType'
 //error: redeclaration of symbol `Msg', first declared at
 
-[ChildProc=any]
 protocol redeclMessage {
 
     // can't declare two messages with the same name
diff --git a/ipc/ipdl/test/ipdl/error/redeclParamReturn.ipdl b/ipc/ipdl/test/ipdl/error/redeclParamReturn.ipdl
index 71a1532bb226..ccdcbbe0d13f 100644
--- a/ipc/ipdl/test/ipdl/error/redeclParamReturn.ipdl
+++ b/ipc/ipdl/test/ipdl/error/redeclParamReturn.ipdl
@@ -1,6 +1,5 @@
 //error: redeclaration of symbol `f', first declared at
 
-[ChildProc=any]
 sync protocol redeclParamReturn {
 
     // it's an error to name a parameter with the same id as a return
diff --git a/ipc/ipdl/test/ipdl/error/shmem.ipdl b/ipc/ipdl/test/ipdl/error/shmem.ipdl
index 4511ce65ddc4..7f4326ccf510 100644
--- a/ipc/ipdl/test/ipdl/error/shmem.ipdl
+++ b/ipc/ipdl/test/ipdl/error/shmem.ipdl
@@ -3,7 +3,6 @@
 
 using class mozilla::ipc::Shmem from "mozilla/ipc/Shmem.h";      // redeclaration
 
-[ChildProc=any]
 protocol shmem {
 child: async Msg(Shmem s);
 };
diff --git a/ipc/ipdl/test/ipdl/error/structRedecl.ipdl b/ipc/ipdl/test/ipdl/error/structRedecl.ipdl
index 37d87d6627b1..03a555787730 100644
--- a/ipc/ipdl/test/ipdl/error/structRedecl.ipdl
+++ b/ipc/ipdl/test/ipdl/error/structRedecl.ipdl
@@ -5,7 +5,6 @@ struct Redecl {
     double a;
 };
 
-[ChildProc=any]
 protocol structRedecl {
 child: async __delete__();
 };
diff --git a/ipc/ipdl/test/ipdl/error/structUnknownField.ipdl b/ipc/ipdl/test/ipdl/error/structUnknownField.ipdl
index e8702a9b7843..ac92edee234f 100644
--- a/ipc/ipdl/test/ipdl/error/structUnknownField.ipdl
+++ b/ipc/ipdl/test/ipdl/error/structUnknownField.ipdl
@@ -4,7 +4,6 @@ struct S {
     Foobers i;
 };
 
-[ChildProc=any]
 protocol structUnknownField {
 child: async __delete__(S s);
 };
diff --git a/ipc/ipdl/test/ipdl/error/syncMessageCompress.ipdl b/ipc/ipdl/test/ipdl/error/syncMessageCompress.ipdl
index 0a3b63be2ce1..376f2ae2dd52 100644
--- a/ipc/ipdl/test/ipdl/error/syncMessageCompress.ipdl
+++ b/ipc/ipdl/test/ipdl/error/syncMessageCompress.ipdl
@@ -1,6 +1,5 @@
 //error: message `foo' in protocol `syncMessageCompress' requests compression but is not async
 
-[ChildProc=any]
 sync protocol syncMessageCompress {
 parent:
     [Compress] sync foo();
diff --git a/ipc/ipdl/test/ipdl/error/syncParentToChild.ipdl b/ipc/ipdl/test/ipdl/error/syncParentToChild.ipdl
index 8ce7c0be477a..bd6c8bc5b1db 100644
--- a/ipc/ipdl/test/ipdl/error/syncParentToChild.ipdl
+++ b/ipc/ipdl/test/ipdl/error/syncParentToChild.ipdl
@@ -1,6 +1,5 @@
 //error: sync parent-to-child messages are verboten (here, message `Msg' in protocol `syncParentToChild')
 
-[ChildProc=any]
 intr protocol syncParentToChild {
 
     // can't declare sync parent-to-child messages
diff --git a/ipc/ipdl/test/ipdl/error/tooWeakIntrAsync.ipdl b/ipc/ipdl/test/ipdl/error/tooWeakIntrAsync.ipdl
index 7dad5e68efbb..220e4c3c28e1 100644
--- a/ipc/ipdl/test/ipdl/error/tooWeakIntrAsync.ipdl
+++ b/ipc/ipdl/test/ipdl/error/tooWeakIntrAsync.ipdl
@@ -1,6 +1,5 @@
 //error: message `Msg' requires more powerful send semantics than its protocol `tooWeakIntrAsync' provides
 
-[ChildProc=any]
 protocol tooWeakIntrAsync {
 
     // it's an error to declare an async protocol with an intr message
diff --git a/ipc/ipdl/test/ipdl/error/tooWeakIntrSync.ipdl b/ipc/ipdl/test/ipdl/error/tooWeakIntrSync.ipdl
index a56e884e735e..4c3b61d0d9bd 100644
--- a/ipc/ipdl/test/ipdl/error/tooWeakIntrSync.ipdl
+++ b/ipc/ipdl/test/ipdl/error/tooWeakIntrSync.ipdl
@@ -1,6 +1,5 @@
 //error: message `Msg' requires more powerful send semantics than its protocol `tooWeakIntrSync' provides
 
-[ChildProc=any]
 sync protocol tooWeakIntrSync {
 
     // it's an error to declare a sync protocol with an interrupt message
diff --git a/ipc/ipdl/test/ipdl/error/tooWeakSyncAsync.ipdl b/ipc/ipdl/test/ipdl/error/tooWeakSyncAsync.ipdl
index 8ebbfd25daba..49e4d3b75bab 100644
--- a/ipc/ipdl/test/ipdl/error/tooWeakSyncAsync.ipdl
+++ b/ipc/ipdl/test/ipdl/error/tooWeakSyncAsync.ipdl
@@ -1,6 +1,5 @@
 //error: message `Msg' requires more powerful send semantics than its protocol `tooWeakSyncAsync' provides
 
-[ChildProc=any]
 protocol tooWeakSyncAsync {
 
     // it's an error to declare an async protocol with a sync message
diff --git a/ipc/ipdl/test/ipdl/error/twoprotocols.ipdl b/ipc/ipdl/test/ipdl/error/twoprotocols.ipdl
index 93222292a5d0..7e2a51a61aee 100644
--- a/ipc/ipdl/test/ipdl/error/twoprotocols.ipdl
+++ b/ipc/ipdl/test/ipdl/error/twoprotocols.ipdl
@@ -2,12 +2,10 @@
 
 //error: only one protocol definition per file
 
-[ChildProc=any]
 protocol p1 {
 child: async Msg();
 };
 
-[ChildProc=any]
 protocol p2 {
 child: async Msg();
 };
diff --git a/ipc/ipdl/test/ipdl/error/undeclParamType.ipdl b/ipc/ipdl/test/ipdl/error/undeclParamType.ipdl
index efc21f05298e..3f93e747e111 100644
--- a/ipc/ipdl/test/ipdl/error/undeclParamType.ipdl
+++ b/ipc/ipdl/test/ipdl/error/undeclParamType.ipdl
@@ -1,6 +1,5 @@
 //error: argument typename `FARGLEGARGLE' of message `Msg' has not been declared
 
-[ChildProc=any]
 protocol undeclParamType {
 
 child: async Msg(FARGLEGARGLE p);
diff --git a/ipc/ipdl/test/ipdl/error/undeclProtocol.ipdl b/ipc/ipdl/test/ipdl/error/undeclProtocol.ipdl
index 19532e3b9c10..cddf57267f1f 100644
--- a/ipc/ipdl/test/ipdl/error/undeclProtocol.ipdl
+++ b/ipc/ipdl/test/ipdl/error/undeclProtocol.ipdl
@@ -1,6 +1,5 @@
 //error: protocol `undeclared', managed by `undeclProtocol', has not been declared
 
-[ChildProc=any]
 protocol undeclProtocol {
     manages undeclared;
 
diff --git a/ipc/ipdl/test/ipdl/error/undeclReturnType.ipdl b/ipc/ipdl/test/ipdl/error/undeclReturnType.ipdl
index 87fe0d622305..2f353a1957d9 100644
--- a/ipc/ipdl/test/ipdl/error/undeclReturnType.ipdl
+++ b/ipc/ipdl/test/ipdl/error/undeclReturnType.ipdl
@@ -1,6 +1,5 @@
 //error: argument typename `FARGLEGARGLE' of message `Msg' has not been declared
 
-[ChildProc=any]
 sync protocol undeclReturnType {
 
 child:  sync Msg() returns (FARGLEGARGLE r);
diff --git a/ipc/ipdl/test/ipdl/error/undefMutualRecStruct.ipdl b/ipc/ipdl/test/ipdl/error/undefMutualRecStruct.ipdl
index 79fa3729cc38..5ede1d82996b 100644
--- a/ipc/ipdl/test/ipdl/error/undefMutualRecStruct.ipdl
+++ b/ipc/ipdl/test/ipdl/error/undefMutualRecStruct.ipdl
@@ -6,7 +6,6 @@ struct X { Y y; };
 struct Y { Z z; };
 struct Z { X x; };
 
-[ChildProc=any]
 protocol undefMutualRecStruct {
 child: async __delete__(X x);
 };
diff --git a/ipc/ipdl/test/ipdl/error/undefMutualRecStructUnion.ipdl b/ipc/ipdl/test/ipdl/error/undefMutualRecStructUnion.ipdl
index 09e7116a68d1..0e88c126e0e9 100644
--- a/ipc/ipdl/test/ipdl/error/undefMutualRecStructUnion.ipdl
+++ b/ipc/ipdl/test/ipdl/error/undefMutualRecStructUnion.ipdl
@@ -6,7 +6,6 @@ struct X { Y y; };
 union Y { Z; };
 struct Z { X x; };
 
-[ChildProc=any]
 protocol undefMutualRecStructUnion {
 child: async __delete__(X x);
 };
diff --git a/ipc/ipdl/test/ipdl/error/undefMutualRecUnion.ipdl b/ipc/ipdl/test/ipdl/error/undefMutualRecUnion.ipdl
index 497836ba4f3b..3fc99bbb95a5 100644
--- a/ipc/ipdl/test/ipdl/error/undefMutualRecUnion.ipdl
+++ b/ipc/ipdl/test/ipdl/error/undefMutualRecUnion.ipdl
@@ -6,7 +6,6 @@ union X { Y; };
 union Y { Z; };
 union Z { X; };
 
-[ChildProc=any]
 protocol undefMutualRecUnion {
 child: async __delete__(X x);
 };
diff --git a/ipc/ipdl/test/ipdl/error/undefSelfRecStruct.ipdl b/ipc/ipdl/test/ipdl/error/undefSelfRecStruct.ipdl
index 1c23da1a7714..15fc45abcd59 100644
--- a/ipc/ipdl/test/ipdl/error/undefSelfRecStruct.ipdl
+++ b/ipc/ipdl/test/ipdl/error/undefSelfRecStruct.ipdl
@@ -2,7 +2,6 @@
 
 struct X { X x; };
 
-[ChildProc=any]
 protocol undefSelfRecStruct {
 child: async __delete__(X x);
 };
diff --git a/ipc/ipdl/test/ipdl/error/undefSelfRecUnion.ipdl b/ipc/ipdl/test/ipdl/error/undefSelfRecUnion.ipdl
index 2c7572f11daa..951f916c5748 100644
--- a/ipc/ipdl/test/ipdl/error/undefSelfRecUnion.ipdl
+++ b/ipc/ipdl/test/ipdl/error/undefSelfRecUnion.ipdl
@@ -2,7 +2,6 @@
 
 union X { X; };
 
-[ChildProc=any]
 protocol undefSelfRecUnion {
 child: async __delete__(X x);
 };
diff --git a/ipc/ipdl/test/ipdl/error/unknownIntrMessage.ipdl b/ipc/ipdl/test/ipdl/error/unknownIntrMessage.ipdl
index 7ce415aba08e..4790232685bb 100644
--- a/ipc/ipdl/test/ipdl/error/unknownIntrMessage.ipdl
+++ b/ipc/ipdl/test/ipdl/error/unknownIntrMessage.ipdl
@@ -1,6 +1,5 @@
 //error: Unknown sync IPC message unknownIntrMessage::Msg
 
-[ChildProc=any]
 intr protocol unknownIntrMessage {
 parent:
     [LegacyIntr] intr Msg();
diff --git a/ipc/ipdl/test/ipdl/error/unknownSyncMessage.ipdl b/ipc/ipdl/test/ipdl/error/unknownSyncMessage.ipdl
index ab1baecd3513..be2cfad0cc88 100644
--- a/ipc/ipdl/test/ipdl/error/unknownSyncMessage.ipdl
+++ b/ipc/ipdl/test/ipdl/error/unknownSyncMessage.ipdl
@@ -1,6 +1,5 @@
 //error: Unknown sync IPC message unknownSyncMessage::Msg
 
-[ChildProc=any]
 sync protocol unknownSyncMessage {
 parent:
     sync Msg();
diff --git a/ipc/ipdl/test/ipdl/ok/PAsyncReturn.ipdl b/ipc/ipdl/test/ipdl/ok/PAsyncReturn.ipdl
index 5deae9216b1d..89c2a7c6473d 100644
--- a/ipc/ipdl/test/ipdl/ok/PAsyncReturn.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PAsyncReturn.ipdl
@@ -2,7 +2,6 @@
 
 //error: asynchronous message `Msg' declares return values
 
-[ChildProc=any]
 protocol PAsyncReturn {
 child:
     async Msg() returns(int32_t aNumber);
diff --git a/ipc/ipdl/test/ipdl/ok/PDelete.ipdl b/ipc/ipdl/test/ipdl/ok/PDelete.ipdl
index 006c73dc0dc7..f2f85fd7faaa 100644
--- a/ipc/ipdl/test/ipdl/ok/PDelete.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PDelete.ipdl
@@ -1,6 +1,5 @@
 include protocol PDeleteSub;
 
-[ChildProc=any]
 sync protocol PDelete {
     manages PDeleteSub;
 
diff --git a/ipc/ipdl/test/ipdl/ok/PEndpointDecl.ipdl b/ipc/ipdl/test/ipdl/ok/PEndpointDecl.ipdl
index f8fe51864a2b..25f58f3f6354 100644
--- a/ipc/ipdl/test/ipdl/ok/PEndpointDecl.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PEndpointDecl.ipdl
@@ -9,7 +9,6 @@ struct Whatever {
 
 namespace mozilla {
 
-[ChildProc=any]
 protocol PEndpointDecl {
   child:
     async Message(Endpoint<PEndpointDeclParent> aEndpointParent,
diff --git a/ipc/ipdl/test/ipdl/ok/PEndpointUse.ipdl b/ipc/ipdl/test/ipdl/ok/PEndpointUse.ipdl
index 8fde19c8e509..0c776b359ccb 100644
--- a/ipc/ipdl/test/ipdl/ok/PEndpointUse.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PEndpointUse.ipdl
@@ -2,7 +2,6 @@ include protocol PEndpointDecl;
 
 // Basic test that Endpoint types are declared for included protocols.
 
-[ChildProc=any]
 protocol PEndpointUse {
   child:
     async Message(Endpoint<PEndpointDeclParent> aEndpointParent,
diff --git a/ipc/ipdl/test/ipdl/ok/PExtendedAttrMultipleAttributes.ipdl b/ipc/ipdl/test/ipdl/ok/PExtendedAttrMultipleAttributes.ipdl
index ce49ed8d2ace..4b1c9085b766 100644
--- a/ipc/ipdl/test/ipdl/ok/PExtendedAttrMultipleAttributes.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PExtendedAttrMultipleAttributes.ipdl
@@ -1,5 +1,4 @@
-[NestedUpTo=inside_sync, NeedsOtherPid, ChildProc=any]
-async protocol PExtendedAttrMultipleAttributes {
+[NestedUpTo=inside_sync, NeedsOtherPid] async protocol PExtendedAttrMultipleAttributes {
 parent:
     async Msg();
 };
diff --git a/ipc/ipdl/test/ipdl/ok/PLazySend.ipdl b/ipc/ipdl/test/ipdl/ok/PLazySend.ipdl
index e67b35a1534a..1bc56a3c6fb1 100644
--- a/ipc/ipdl/test/ipdl/ok/PLazySend.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PLazySend.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 protocol PLazySend {
 child:
     [LazySend] async foo();
diff --git a/ipc/ipdl/test/ipdl/ok/PManagedEndpointManager.ipdl b/ipc/ipdl/test/ipdl/ok/PManagedEndpointManager.ipdl
index 2ae381c72b29..4c95b7880c23 100644
--- a/ipc/ipdl/test/ipdl/ok/PManagedEndpointManager.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PManagedEndpointManager.ipdl
@@ -2,7 +2,6 @@ include protocol PManagedEndpointDecl;
 
 namespace mozilla {
 
-[ChildProc=any]
 protocol PManagedEndpointManager {
   manages PManagedEndpointDecl;
 
diff --git a/ipc/ipdl/test/ipdl/ok/PManualDealloc_manager.ipdl b/ipc/ipdl/test/ipdl/ok/PManualDealloc_manager.ipdl
index d425a6781fb2..224c7a5e46cc 100644
--- a/ipc/ipdl/test/ipdl/ok/PManualDealloc_manager.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PManualDealloc_manager.ipdl
@@ -2,7 +2,6 @@ include protocol PManualDealloc;
 
 // [ManualDealloc] types must have a manager, as all toplevel protocols are
 // refcounted.
-[ChildProc=any]
 async protocol PManualDealloc_manager {
     manages PManualDealloc;
 };
diff --git a/ipc/ipdl/test/ipdl/ok/PMessageTainted.ipdl b/ipc/ipdl/test/ipdl/ok/PMessageTainted.ipdl
index deb10fb7acf9..0733117be915 100644
--- a/ipc/ipdl/test/ipdl/ok/PMessageTainted.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PMessageTainted.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 intr protocol PMessageTainted {
 child:
     [Tainted] async foo();
diff --git a/ipc/ipdl/test/ipdl/ok/PMessageTaintedWithPassback.ipdl b/ipc/ipdl/test/ipdl/ok/PMessageTaintedWithPassback.ipdl
index 8db2c8b742e0..1d03e97e7394 100644
--- a/ipc/ipdl/test/ipdl/ok/PMessageTaintedWithPassback.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PMessageTaintedWithPassback.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 intr protocol PMessageTaintedWithPassback {
 child:
     [Tainted] async foo([NoTaint=passback] int id);
diff --git a/ipc/ipdl/test/ipdl/ok/PMyManager.ipdl b/ipc/ipdl/test/ipdl/ok/PMyManager.ipdl
index 4ed2706ffd6e..5e82f53ccaac 100644
--- a/ipc/ipdl/test/ipdl/ok/PMyManager.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PMyManager.ipdl
@@ -14,7 +14,6 @@ namespace myns {
     MyOtherData;
 };
 
-[ChildProc=any]
 sync protocol PMyManager {
   manages PMyManaged;
   parent:
diff --git a/ipc/ipdl/test/ipdl/ok/PNested.ipdl b/ipc/ipdl/test/ipdl/ok/PNested.ipdl
index 94865bca6b3b..4368f2a1abe2 100644
--- a/ipc/ipdl/test/ipdl/ok/PNested.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PNested.ipdl
@@ -1,5 +1,4 @@
-[NestedUpTo=inside_cpow, ChildProc=any]
-sync protocol PNested {
+[NestedUpTo=inside_cpow] sync protocol PNested {
 parent:
   [Nested=not] async NotNested();
   [Nested=inside_sync] sync InsideSync();
diff --git a/ipc/ipdl/test/ipdl/ok/PNullable.ipdl b/ipc/ipdl/test/ipdl/ok/PNullable.ipdl
index b7b21ff88577..51601d59f102 100644
--- a/ipc/ipdl/test/ipdl/ok/PNullable.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PNullable.ipdl
@@ -9,7 +9,6 @@ union Union {
     nullable nsIURI?;
 };
 
-[ChildProc=any]
 protocol PNullable {
 child:
     async Msg(nullable PNullable n);
diff --git a/ipc/ipdl/test/ipdl/ok/PSideImpl.ipdl b/ipc/ipdl/test/ipdl/ok/PSideImpl.ipdl
index 4ebb1b8ec3d5..0858734c7400 100644
--- a/ipc/ipdl/test/ipdl/ok/PSideImpl.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PSideImpl.ipdl
@@ -1,4 +1,4 @@
-[ParentImpl=virtual, ChildImpl="mozilla::FooBarImpl", ChildProc=any]
+[ParentImpl=virtual, ChildImpl="mozilla::FooBarImpl"]
 async protocol PSideImpl {
  parent:
   async __delete__();
diff --git a/ipc/ipdl/test/ipdl/ok/PStruct.ipdl b/ipc/ipdl/test/ipdl/ok/PStruct.ipdl
index f76f7db98fa8..c670a83b0b6c 100644
--- a/ipc/ipdl/test/ipdl/ok/PStruct.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PStruct.ipdl
@@ -3,7 +3,6 @@ struct S {
     double d;
 };
 
-[ChildProc=any]
 sync protocol PStruct {
 parent:
     sync test(S s) returns (S ss);
diff --git a/ipc/ipdl/test/ipdl/ok/PStructComparable.ipdl b/ipc/ipdl/test/ipdl/ok/PStructComparable.ipdl
index 89576368eca5..ca1f654bb55d 100644
--- a/ipc/ipdl/test/ipdl/ok/PStructComparable.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PStructComparable.ipdl
@@ -3,7 +3,6 @@
     double d;
 };
 
-[ChildProc=any]
 sync protocol PStructComparable {
 parent:
     sync test(S s) returns (S ss);
diff --git a/ipc/ipdl/test/ipdl/ok/PSyncSyncManager.ipdl b/ipc/ipdl/test/ipdl/ok/PSyncSyncManager.ipdl
index d3fc236ff882..00f9dead477c 100644
--- a/ipc/ipdl/test/ipdl/ok/PSyncSyncManager.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PSyncSyncManager.ipdl
@@ -4,8 +4,7 @@ include protocol PSyncSyncManagee;
  * in the Rust IPDL parser that was treating "sync" like "async" in the
  * nested case.
  */
-[NestedUpTo=not, ChildProc=any]
-sync protocol PSyncSyncManager {
+[NestedUpTo=not] sync protocol PSyncSyncManager {
     manages PSyncSyncManagee;
 parent:
     async PSyncSyncManagee();
diff --git a/ipc/ipdl/test/ipdl/ok/PUniquePtrBasic.ipdl b/ipc/ipdl/test/ipdl/ok/PUniquePtrBasic.ipdl
index 097dd0468425..caffd0dbbc76 100644
--- a/ipc/ipdl/test/ipdl/ok/PUniquePtrBasic.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PUniquePtrBasic.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 protocol PUniquePtrBasic {
 child:
     async Msg(UniquePtr<int> maybe);
diff --git a/ipc/ipdl/test/ipdl/ok/PUniquePtrOfActors.ipdl b/ipc/ipdl/test/ipdl/ok/PUniquePtrOfActors.ipdl
index 24631db712c8..ce67f23c68c0 100644
--- a/ipc/ipdl/test/ipdl/ok/PUniquePtrOfActors.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PUniquePtrOfActors.ipdl
@@ -1,6 +1,5 @@
 include protocol PUniquePtrOfActorsSub;
 
-[ChildProc=any]
 protocol PUniquePtrOfActors {
     manages PUniquePtrOfActorsSub;
 
diff --git a/ipc/ipdl/test/ipdl/ok/PUniquePtrRecUnion.ipdl b/ipc/ipdl/test/ipdl/ok/PUniquePtrRecUnion.ipdl
index 40ac466b4079..4a0b9e7299d5 100644
--- a/ipc/ipdl/test/ipdl/ok/PUniquePtrRecUnion.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PUniquePtrRecUnion.ipdl
@@ -14,7 +14,6 @@ union Z {
     X;
 };
 
-[ChildProc=any]
 protocol PUniquePtrRecUnion {
 child:
     async Test(X x, Y y, Z z);
diff --git a/ipc/ipdl/test/ipdl/ok/PUniquePtrUnion.ipdl b/ipc/ipdl/test/ipdl/ok/PUniquePtrUnion.ipdl
index de4529c6395f..d75633998035 100644
--- a/ipc/ipdl/test/ipdl/ok/PUniquePtrUnion.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PUniquePtrUnion.ipdl
@@ -4,7 +4,6 @@ union UniquePtrUnion {
     double;
 };
 
-[ChildProc=any]
 sync protocol PUniquePtrUnion {
 parent:
     async Msg(UniquePtrUnion u, UniquePtr<UniquePtrUnion> au) returns (UniquePtrUnion r);
diff --git a/ipc/ipdl/test/ipdl/ok/PVirtualSendImpl.ipdl b/ipc/ipdl/test/ipdl/ok/PVirtualSendImpl.ipdl
index ff091089652c..042e7624752c 100644
--- a/ipc/ipdl/test/ipdl/ok/PVirtualSendImpl.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PVirtualSendImpl.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 async protocol PVirtualSendImpl
 {
 child:
diff --git a/ipc/ipdl/test/ipdl/ok/Pactorparam.ipdl b/ipc/ipdl/test/ipdl/ok/Pactorparam.ipdl
index bb7bb8551863..0cba299cf563 100644
--- a/ipc/ipdl/test/ipdl/ok/Pactorparam.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Pactorparam.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 protocol Pactorparam {
 
 child: async Msg(Pactorparam p);
diff --git a/ipc/ipdl/test/ipdl/ok/Pactorreturn.ipdl b/ipc/ipdl/test/ipdl/ok/Pactorreturn.ipdl
index 4e8e53a9d65e..99d0d3622570 100644
--- a/ipc/ipdl/test/ipdl/ok/Pactorreturn.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Pactorreturn.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 sync protocol Pactorreturn {
 
 parent:
diff --git a/ipc/ipdl/test/ipdl/ok/Parray_Basic.ipdl b/ipc/ipdl/test/ipdl/ok/Parray_Basic.ipdl
index 7ce682f15410..811c01f32403 100644
--- a/ipc/ipdl/test/ipdl/ok/Parray_Basic.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Parray_Basic.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 protocol Parray_Basic {
 child:
     async Msg(int[] array);
diff --git a/ipc/ipdl/test/ipdl/ok/Parray_OfActors.ipdl b/ipc/ipdl/test/ipdl/ok/Parray_OfActors.ipdl
index 170f4e902ae2..b084c2c46483 100644
--- a/ipc/ipdl/test/ipdl/ok/Parray_OfActors.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Parray_OfActors.ipdl
@@ -1,6 +1,5 @@
 include protocol Parray_OfActorsSub;
 
-[ChildProc=any]
 protocol Parray_OfActors {
     manages Parray_OfActorsSub;
 
diff --git a/ipc/ipdl/test/ipdl/ok/Parray_Union.ipdl b/ipc/ipdl/test/ipdl/ok/Parray_Union.ipdl
index 2733d5fc048e..33c94e7ae533 100644
--- a/ipc/ipdl/test/ipdl/ok/Parray_Union.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Parray_Union.ipdl
@@ -4,7 +4,6 @@ union Union {
     double;
 };
 
-[ChildProc=any]
 sync protocol Parray_Union {
 parent:
     sync Msg(Union u, Union[] au) returns (Union r);
diff --git a/ipc/ipdl/test/ipdl/ok/PbasicUsing.ipdl b/ipc/ipdl/test/ipdl/ok/PbasicUsing.ipdl
index 94d57b08d022..ac4df3a258f9 100644
--- a/ipc/ipdl/test/ipdl/ok/PbasicUsing.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PbasicUsing.ipdl
@@ -44,7 +44,6 @@ union SomeUnion
   SomeMoveonlySendStruct;
 };
 
-[ChildProc=any]
 protocol PbasicUsing {
 child:
     async Msg(SomeUnion foo);
diff --git a/ipc/ipdl/test/ipdl/ok/Pbuiltins.ipdl b/ipc/ipdl/test/ipdl/ok/Pbuiltins.ipdl
index 3cd023a0b653..4085dc6d95a2 100644
--- a/ipc/ipdl/test/ipdl/ok/Pbuiltins.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Pbuiltins.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 protocol Pbuiltins {
 
     // sanity-check that "essential" builtins are being declared
diff --git a/ipc/ipdl/test/ipdl/ok/Pbytebuf.ipdl b/ipc/ipdl/test/ipdl/ok/Pbytebuf.ipdl
index a0ceac937f1e..016702053e95 100644
--- a/ipc/ipdl/test/ipdl/ok/Pbytebuf.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Pbytebuf.ipdl
@@ -3,7 +3,6 @@ union Foo {
     ByteBuf;
 };
 
-[ChildProc=any]
 intr protocol Pbytebuf {
 parent:
     async Msg(ByteBuf s, Foo f);
diff --git a/ipc/ipdl/test/ipdl/ok/Pempty.ipdl b/ipc/ipdl/test/ipdl/ok/Pempty.ipdl
index 4ab603dbc8ba..61b511bec6ca 100644
--- a/ipc/ipdl/test/ipdl/ok/Pempty.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Pempty.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 protocol Pempty {
 child: async Msg();
 };
diff --git a/ipc/ipdl/test/ipdl/ok/PemptyStruct.ipdl b/ipc/ipdl/test/ipdl/ok/PemptyStruct.ipdl
index a3317cb87283..a067bf71da53 100644
--- a/ipc/ipdl/test/ipdl/ok/PemptyStruct.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PemptyStruct.ipdl
@@ -1,4 +1,3 @@
 struct empty { };
 
-[ChildProc=any]
 protocol PemptyStruct { child:  async __delete__(); };
diff --git a/ipc/ipdl/test/ipdl/ok/PheaderProto.ipdl b/ipc/ipdl/test/ipdl/ok/PheaderProto.ipdl
index 5c9af7c3f912..7ae285042eff 100644
--- a/ipc/ipdl/test/ipdl/ok/PheaderProto.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PheaderProto.ipdl
@@ -2,7 +2,6 @@ include header;
 
 namespace c {
 
-[ChildProc=any]
 protocol PheaderProto {
 child:
     async __delete__(foo a, baz b, Inner1 c, Inner2 d, X x);
diff --git a/ipc/ipdl/test/ipdl/ok/PintrProtocol.ipdl b/ipc/ipdl/test/ipdl/ok/PintrProtocol.ipdl
index 4b663327e6b9..a931a7eb9adf 100644
--- a/ipc/ipdl/test/ipdl/ok/PintrProtocol.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PintrProtocol.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 intr protocol PintrProtocol {
 
     // sanity check of Interrupt protocols
diff --git a/ipc/ipdl/test/ipdl/ok/Pjetpack.ipdl b/ipc/ipdl/test/ipdl/ok/Pjetpack.ipdl
index 7744f59f8fd6..190732485dc8 100644
--- a/ipc/ipdl/test/ipdl/ok/Pjetpack.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Pjetpack.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 sync protocol Pjetpack {
 child:
     async __delete__();
diff --git a/ipc/ipdl/test/ipdl/ok/PmanageSelf_Toplevel.ipdl b/ipc/ipdl/test/ipdl/ok/PmanageSelf_Toplevel.ipdl
index 15be35f838bd..70b5fe8a9b78 100644
--- a/ipc/ipdl/test/ipdl/ok/PmanageSelf_Toplevel.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PmanageSelf_Toplevel.ipdl
@@ -1,6 +1,5 @@
 include protocol PmanageSelf;
 
-[ChildProc=any]
 protocol PmanageSelf_Toplevel {
     manages PmanageSelf;
 
diff --git a/ipc/ipdl/test/ipdl/ok/PmanagerProtocol.ipdl b/ipc/ipdl/test/ipdl/ok/PmanagerProtocol.ipdl
index 28483426d332..40d1de31b01e 100644
--- a/ipc/ipdl/test/ipdl/ok/PmanagerProtocol.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PmanagerProtocol.ipdl
@@ -2,7 +2,6 @@ include protocol PmanagedProtocol;
 
 // sanity check of managed/manager protocols
 
-[ChildProc=any]
 protocol PmanagerProtocol {
     manages PmanagedProtocol;
 
diff --git a/ipc/ipdl/test/ipdl/ok/Pmaybe_Basic.ipdl b/ipc/ipdl/test/ipdl/ok/Pmaybe_Basic.ipdl
index 52243d5ca371..a0bbccd87448 100644
--- a/ipc/ipdl/test/ipdl/ok/Pmaybe_Basic.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Pmaybe_Basic.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 protocol Pmaybe_Basic {
 child:
     async Msg(int? maybe);
diff --git a/ipc/ipdl/test/ipdl/ok/Pmaybe_OfActors.ipdl b/ipc/ipdl/test/ipdl/ok/Pmaybe_OfActors.ipdl
index 2252c328275b..430faa9ae76b 100644
--- a/ipc/ipdl/test/ipdl/ok/Pmaybe_OfActors.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Pmaybe_OfActors.ipdl
@@ -1,6 +1,5 @@
 include protocol Pmaybe_OfActorsSub;
 
-[ChildProc=any]
 protocol Pmaybe_OfActors {
     manages Pmaybe_OfActorsSub;
 
diff --git a/ipc/ipdl/test/ipdl/ok/Pmaybe_Union.ipdl b/ipc/ipdl/test/ipdl/ok/Pmaybe_Union.ipdl
index 5701b08fd97f..67f24cb794aa 100644
--- a/ipc/ipdl/test/ipdl/ok/Pmaybe_Union.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Pmaybe_Union.ipdl
@@ -4,7 +4,6 @@ union MaybeUnion {
     double;
 };
 
-[ChildProc=any]
 sync protocol Pmaybe_Union {
 parent:
     async Msg(MaybeUnion u, MaybeUnion? au) returns (MaybeUnion r);
diff --git a/ipc/ipdl/test/ipdl/ok/Pmedia.ipdl b/ipc/ipdl/test/ipdl/ok/Pmedia.ipdl
index e0f95d2a3416..0a8076a43307 100644
--- a/ipc/ipdl/test/ipdl/ok/Pmedia.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Pmedia.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 sync protocol Pmedia {
 child:
     async __delete__();
diff --git a/ipc/ipdl/test/ipdl/ok/PmessageCompress.ipdl b/ipc/ipdl/test/ipdl/ok/PmessageCompress.ipdl
index 7e14c888ddd8..53dfe9098fc8 100644
--- a/ipc/ipdl/test/ipdl/ok/PmessageCompress.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PmessageCompress.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 intr protocol PmessageCompress {
 child:
     [Compress] async foo();
diff --git a/ipc/ipdl/test/ipdl/ok/PmultiManager1.ipdl b/ipc/ipdl/test/ipdl/ok/PmultiManager1.ipdl
index ec384124224c..b0654a8c4f50 100644
--- a/ipc/ipdl/test/ipdl/ok/PmultiManager1.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PmultiManager1.ipdl
@@ -1,6 +1,5 @@
 include protocol PmultiManaged;
 
-[ChildProc=any]
 protocol PmultiManager1 {
     manages PmultiManaged;
 
diff --git a/ipc/ipdl/test/ipdl/ok/PmultiManager2.ipdl b/ipc/ipdl/test/ipdl/ok/PmultiManager2.ipdl
index b8295fd05722..c03f05a17360 100644
--- a/ipc/ipdl/test/ipdl/ok/PmultiManager2.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PmultiManager2.ipdl
@@ -1,6 +1,5 @@
 include protocol PmultiManaged;
 
-[ChildProc=any]
 protocol PmultiManager2 {
     manages PmultiManaged;
 
diff --git a/ipc/ipdl/test/ipdl/ok/PmultipleUsingCxxTypes.ipdl b/ipc/ipdl/test/ipdl/ok/PmultipleUsingCxxTypes.ipdl
index 5d5ae5e9a807..fa63b5b4b01e 100644
--- a/ipc/ipdl/test/ipdl/ok/PmultipleUsingCxxTypes.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PmultipleUsingCxxTypes.ipdl
@@ -1,7 +1,6 @@
 using struct mozilla::void_t from "mozilla/ipc/IPCCore.h";
 using struct mozilla::void_t from "mozilla/ipc/IPCCore.h";
 
-[ChildProc=any]
 protocol PmultipleUsingCxxTypes {
 child:
     async Msg(void_t foo);
diff --git a/ipc/ipdl/test/ipdl/ok/PmutualRecStructUnion.ipdl b/ipc/ipdl/test/ipdl/ok/PmutualRecStructUnion.ipdl
index b28df7969b32..0fe5501a09c9 100644
--- a/ipc/ipdl/test/ipdl/ok/PmutualRecStructUnion.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PmutualRecStructUnion.ipdl
@@ -14,7 +14,6 @@ struct Z {
     Y y;
 };
 
-[ChildProc=any]
 protocol PmutualRecStructUnion {
 child:
     async Test(X x, Y y, Z z);
diff --git a/ipc/ipdl/test/ipdl/ok/PmutualRecUnion.ipdl b/ipc/ipdl/test/ipdl/ok/PmutualRecUnion.ipdl
index 73c869278ff7..304847e003d1 100644
--- a/ipc/ipdl/test/ipdl/ok/PmutualRecUnion.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PmutualRecUnion.ipdl
@@ -14,7 +14,6 @@ union Z {
     X;
 };
 
-[ChildProc=any]
 protocol PmutualRecUnion {
 child:
     async Test(X x, Y y, Z z);
diff --git a/ipc/ipdl/test/ipdl/ok/Pnamespace_Basic.ipdl b/ipc/ipdl/test/ipdl/ok/Pnamespace_Basic.ipdl
index 3b2f2fa27fe0..4f996d974471 100644
--- a/ipc/ipdl/test/ipdl/ok/Pnamespace_Basic.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Pnamespace_Basic.ipdl
@@ -2,7 +2,6 @@ namespace basic {
 
 // sanity check of namespaced protocols
 
-[ChildProc=any]
 protocol Pnamespace_Basic {
 
 child:
diff --git a/ipc/ipdl/test/ipdl/ok/PnoRedeclCrossMessage.ipdl b/ipc/ipdl/test/ipdl/ok/PnoRedeclCrossMessage.ipdl
index 30c7179e8c40..d353a8c07ceb 100644
--- a/ipc/ipdl/test/ipdl/ok/PnoRedeclCrossMessage.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PnoRedeclCrossMessage.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 protocol PnoRedeclCrossMessage {
 
     // each message has its own scope for param/return names
diff --git a/ipc/ipdl/test/ipdl/ok/Pplugin.ipdl b/ipc/ipdl/test/ipdl/ok/Pplugin.ipdl
index f7d9352a0819..29c001e67b10 100644
--- a/ipc/ipdl/test/ipdl/ok/Pplugin.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Pplugin.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 intr protocol Pplugin {
 child:
     async __delete__();
diff --git a/ipc/ipdl/test/ipdl/ok/Prio.ipdl b/ipc/ipdl/test/ipdl/ok/Prio.ipdl
index fdda57f784ed..515b3fd68de3 100644
--- a/ipc/ipdl/test/ipdl/ok/Prio.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Prio.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 async protocol Prio
 {
 child:
diff --git a/ipc/ipdl/test/ipdl/ok/PselfRecUnion.ipdl b/ipc/ipdl/test/ipdl/ok/PselfRecUnion.ipdl
index 9d5e3de487f2..7d76c34542f4 100644
--- a/ipc/ipdl/test/ipdl/ok/PselfRecUnion.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PselfRecUnion.ipdl
@@ -4,7 +4,6 @@ union R {
     R;
 };
 
-[ChildProc=any]
 protocol PselfRecUnion {
 child:
     async Test(R r);
diff --git a/ipc/ipdl/test/ipdl/ok/Pshmem.ipdl b/ipc/ipdl/test/ipdl/ok/Pshmem.ipdl
index a46e777d8cf0..0894e9565229 100644
--- a/ipc/ipdl/test/ipdl/ok/Pshmem.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Pshmem.ipdl
@@ -3,7 +3,6 @@ union Foo {
     Shmem;
 };
 
-[ChildProc=any]
 intr protocol Pshmem {
 parent:
     async Msg(Shmem s, Foo f);
diff --git a/ipc/ipdl/test/ipdl/ok/PsyncProtocol.ipdl b/ipc/ipdl/test/ipdl/ok/PsyncProtocol.ipdl
index f73be554e47a..377671b2d62f 100644
--- a/ipc/ipdl/test/ipdl/ok/PsyncProtocol.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PsyncProtocol.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 sync protocol PsyncProtocol {
 
     // sanity check of sync protocols
diff --git a/ipc/ipdl/test/ipdl/ok/PthreeDirections.ipdl b/ipc/ipdl/test/ipdl/ok/PthreeDirections.ipdl
index 6474ca5d0db4..81c8cf604124 100644
--- a/ipc/ipdl/test/ipdl/ok/PthreeDirections.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/PthreeDirections.ipdl
@@ -1,4 +1,3 @@
-[ChildProc=any]
 protocol PthreeDirections {
 
     // sanity check that the three direction specifiers are being accepted
diff --git a/ipc/ipdl/test/ipdl/ok/Punion_Basic.ipdl b/ipc/ipdl/test/ipdl/ok/Punion_Basic.ipdl
index a049d52e7549..697b86e088ac 100644
--- a/ipc/ipdl/test/ipdl/ok/Punion_Basic.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Punion_Basic.ipdl
@@ -3,7 +3,6 @@ union Basic {
     double;
 };
 
-[ChildProc=any]
 sync protocol Punion_Basic {
 
 parent:
diff --git a/ipc/ipdl/test/ipdl/ok/Punion_Comparable.ipdl b/ipc/ipdl/test/ipdl/ok/Punion_Comparable.ipdl
index 05b26f32aa85..c69ac07cc237 100644
--- a/ipc/ipdl/test/ipdl/ok/Punion_Comparable.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Punion_Comparable.ipdl
@@ -3,7 +3,6 @@
     double;
 };
 
-[ChildProc=any]
 sync protocol Punion_Comparable {
 
 parent:
diff --git a/ipc/ipdl/test/ipdl/ok/Punion_Namespaced.ipdl b/ipc/ipdl/test/ipdl/ok/Punion_Namespaced.ipdl
index 4108dfd4df34..9453a561c8cd 100644
--- a/ipc/ipdl/test/ipdl/ok/Punion_Namespaced.ipdl
+++ b/ipc/ipdl/test/ipdl/ok/Punion_Namespaced.ipdl
@@ -10,7 +10,6 @@ union Socks {
 
 namespace puppies {
 
-[ChildProc=any]
 protocol Punion_Namespaced {
 child:
     async Msg(Socks s);
diff --git a/netwerk/ipc/PProxyAutoConfig.ipdl b/netwerk/ipc/PProxyAutoConfig.ipdl
index 7018243fa6b0..105839743346 100644
--- a/netwerk/ipc/PProxyAutoConfig.ipdl
+++ b/netwerk/ipc/PProxyAutoConfig.ipdl
@@ -7,7 +7,6 @@
 namespace mozilla {
 namespace net {
 
-[ChildProc=Socket]
 sync protocol PProxyAutoConfig
 {
 child:
diff --git a/netwerk/ipc/PSocketProcess.ipdl b/netwerk/ipc/PSocketProcess.ipdl
index ede6397fa40b..6defb0059555 100644
--- a/netwerk/ipc/PSocketProcess.ipdl
+++ b/netwerk/ipc/PSocketProcess.ipdl
@@ -87,7 +87,7 @@ struct SocketPorcessInitAttributes {
   FileDescriptor? mSandboxBroker;
 };
 
-[NeedsOtherPid, ChildProc=Socket]
+[NeedsOtherPid]
 sync protocol PSocketProcess
 {
   manages PDNSRequest;
diff --git a/netwerk/ipc/PSocketProcessBackground.ipdl b/netwerk/ipc/PSocketProcessBackground.ipdl
index 8c703a4ae2f6..95d01a9abba7 100644
--- a/netwerk/ipc/PSocketProcessBackground.ipdl
+++ b/netwerk/ipc/PSocketProcessBackground.ipdl
@@ -22,7 +22,6 @@ namespace net {
   * We use this to create several IPC protocols between the socket process
   * and the parent process.
   */
-[ChildProc=Socket]
 sync protocol PSocketProcessBackground
 {
 parent:
diff --git a/netwerk/ipc/PSocketProcessBridge.ipdl b/netwerk/ipc/PSocketProcessBridge.ipdl
index 36c808bfdc58..1179ac8274ff 100644
--- a/netwerk/ipc/PSocketProcessBridge.ipdl
+++ b/netwerk/ipc/PSocketProcessBridge.ipdl
@@ -23,7 +23,7 @@ namespace net {
   * content process and PSocketProcessBridgeParent lives in
   * socket process.
   */
-[NeedsOtherPid, ParentProc=Socket, ChildProc=Content]
+[NeedsOtherPid]
 sync protocol PSocketProcessBridge
 {
 parent:
diff --git a/netwerk/protocol/http/PBackgroundDataBridge.ipdl b/netwerk/protocol/http/PBackgroundDataBridge.ipdl
index d5a3be4faba9..db7c1b6c279a 100644
--- a/netwerk/protocol/http/PBackgroundDataBridge.ipdl
+++ b/netwerk/protocol/http/PBackgroundDataBridge.ipdl
@@ -9,7 +9,6 @@ namespace mozilla {
 namespace net {
 
 //-------------------------------------------------------------------
-[ParentProc=Socket, ChildProc=Content]
 async protocol PBackgroundDataBridge
 {
 child:
diff --git a/netwerk/protocol/websocket/PWebSocketConnection.ipdl b/netwerk/protocol/websocket/PWebSocketConnection.ipdl
index b378320a2b93..f2fc4f203ad0 100644
--- a/netwerk/protocol/websocket/PWebSocketConnection.ipdl
+++ b/netwerk/protocol/websocket/PWebSocketConnection.ipdl
@@ -11,7 +11,6 @@ include "mozilla/ipc/TransportSecurityInfoUtils.h";
 namespace mozilla {
 namespace net {
 
-[ChildProc=Socket]
 protocol PWebSocketConnection
 {
 parent:
diff --git a/security/manager/ssl/PIPCClientCerts.ipdl b/security/manager/ssl/PIPCClientCerts.ipdl
index 5adecae93d02..51ec0dd3b646 100644
--- a/security/manager/ssl/PIPCClientCerts.ipdl
+++ b/security/manager/ssl/PIPCClientCerts.ipdl
@@ -10,7 +10,6 @@ using mozilla::OriginAttributes from "mozilla/ipc/BackgroundUtils.h";
 namespace mozilla {
 namespace psm {
 
-[ChildProc=Socket]
 sync protocol PIPCClientCerts
 {
 parent:
diff --git a/security/manager/ssl/PSelectTLSClientAuthCert.ipdl b/security/manager/ssl/PSelectTLSClientAuthCert.ipdl
index bca7c543d859..e78edc1622ae 100644
--- a/security/manager/ssl/PSelectTLSClientAuthCert.ipdl
+++ b/security/manager/ssl/PSelectTLSClientAuthCert.ipdl
@@ -10,7 +10,6 @@ include PSMIPCTypes;
 namespace mozilla {
 namespace psm {
 
-[ChildProc=Socket]
 protocol PSelectTLSClientAuthCert
 {
 child:
diff --git a/security/manager/ssl/PVerifySSLServerCert.ipdl b/security/manager/ssl/PVerifySSLServerCert.ipdl
index 92a14160cef8..2f178c91797d 100644
--- a/security/manager/ssl/PVerifySSLServerCert.ipdl
+++ b/security/manager/ssl/PVerifySSLServerCert.ipdl
@@ -12,7 +12,6 @@ using mozilla::OriginAttributes from "mozilla/ipc/BackgroundUtils.h";
 namespace mozilla {
 namespace psm {
 
-[ChildProc=Socket]
 protocol PVerifySSLServerCert
 {
 child:
diff --git a/security/sandbox/common/test/PSandboxTesting.ipdl b/security/sandbox/common/test/PSandboxTesting.ipdl
index 1397cfd0e764..8498f4a2353c 100644
--- a/security/sandbox/common/test/PSandboxTesting.ipdl
+++ b/security/sandbox/common/test/PSandboxTesting.ipdl
@@ -6,7 +6,6 @@
 
 namespace mozilla {
 
-[ChildProc=anychild]
 sync protocol PSandboxTesting {
 parent:
   async ReportTestResults(nsCString testName, bool passed, nsCString message);
diff --git a/security/sandbox/win/src/remotesandboxbroker/PRemoteSandboxBroker.ipdl b/security/sandbox/win/src/remotesandboxbroker/PRemoteSandboxBroker.ipdl
index 139380259fe6..7057a2ca4261 100644
--- a/security/sandbox/win/src/remotesandboxbroker/PRemoteSandboxBroker.ipdl
+++ b/security/sandbox/win/src/remotesandboxbroker/PRemoteSandboxBroker.ipdl
@@ -23,7 +23,7 @@ struct LaunchParameters {
   bool enableLogging;
 };
 
-[NeedsOtherPid, NestedUpTo=inside_sync, ChildProc=RemoteSandboxBroker]
+[NeedsOtherPid, NestedUpTo=inside_sync]
 sync protocol PRemoteSandboxBroker
 {
 parent:
diff --git a/toolkit/components/extensions/webrequest/PStreamFilter.ipdl b/toolkit/components/extensions/webrequest/PStreamFilter.ipdl
index d651ba1760ec..80e03cc8cfd5 100644
--- a/toolkit/components/extensions/webrequest/PStreamFilter.ipdl
+++ b/toolkit/components/extensions/webrequest/PStreamFilter.ipdl
@@ -7,7 +7,6 @@ include protocol PBackground;
 namespace mozilla {
 namespace extensions {
 
-[ParentProc=any, ChildProc=any]
 async protocol PStreamFilter
 {
 parent:
diff --git a/tools/profiler/gecko/PProfiler.ipdl b/tools/profiler/gecko/PProfiler.ipdl
index 0dda8d320983..65778b892cfe 100644
--- a/tools/profiler/gecko/PProfiler.ipdl
+++ b/tools/profiler/gecko/PProfiler.ipdl
@@ -14,7 +14,7 @@ namespace mozilla {
 // It is a top-level protocol so that its child endpoint can be on a
 // background thread, so that profiles can be gathered even if the main thread
 // is unresponsive.
-[ChildImpl=virtual, ParentImpl=virtual, ChildProc=anychild]
+[ChildImpl=virtual, ParentImpl=virtual]
 async protocol PProfiler
 {
 child:
diff --git a/widget/windows/filedialog/PWinFileDialog.ipdl b/widget/windows/filedialog/PWinFileDialog.ipdl
index 812db7e103b4..d7f9336e2656 100644
--- a/widget/windows/filedialog/PWinFileDialog.ipdl
+++ b/widget/windows/filedialog/PWinFileDialog.ipdl
@@ -12,7 +12,6 @@ namespace mozilla {
 namespace widget {
 namespace filedialog {
 
-[ChildProc=Utility]
 protocol PWinFileDialog {
 
 child: