Backed out changeset cbef096ccab3 (bug 1836377) for causing mochitest-media failures on test_enumerateDevices.html. CLOSED TREE

dom/media/MediaDevices.cpp

@@ -425,17 +425,12 @@ void MediaDevices::ResumeEnumerateDevices(
 
 void MediaDevices::ResolveEnumerateDevicesPromise(
     Promise* aPromise, const LocalMediaDeviceSet& aDevices) const {
-  nsCOMPtr<nsPIDOMWindowInner> window = GetOwner();
-  auto windowId = window->WindowID();
   nsTArray<RefPtr<MediaDeviceInfo>> infos;
   bool legacy = StaticPrefs::media_devices_enumerate_legacy_enabled();
-  bool capturePermitted =
-      legacy &&
-      MediaManager::Get()->IsActivelyCapturingOrHasAPermission(windowId);
 
   for (const RefPtr<LocalMediaDevice>& device : aDevices) {
     bool exposeInfo = CanExposeInfo(device->Kind()) || legacy;
-    bool exposeLabel = legacy ? capturePermitted : exposeInfo;
+    bool exposeLabel = legacy ? DeviceInformationCanBeExposed() : exposeInfo;
     infos.AppendElement(MakeRefPtr<MediaDeviceInfo>(
         exposeInfo ? device->mID : u""_ns, device->Kind(),
         exposeLabel ? device->mName : u""_ns,
@@ -796,6 +791,10 @@ void MediaDevices::EventListenerAdded(nsAtom* aType) {
   SetupDeviceChangeListener();
 }
 
+bool MediaDevices::DeviceInformationCanBeExposed() const {
+  return mCanExposeCameraInfo || mCanExposeMicrophoneInfo;
+}
+
 JSObject* MediaDevices::WrapObject(JSContext* aCx,
                                    JS::Handle<JSObject*> aGivenProto) {
   return MediaDevices_Binding::Wrap(aCx, this, aGivenProto);

dom/media/MediaDevices.h

@@ -116,6 +116,9 @@ class MediaDevices final : public DOMEventTargetHelper {
   void ResolveEnumerateDevicesPromise(
       Promise* aPromise, const LocalMediaDeviceSet& aDevices) const;
 
+  // See https://www.w3.org/TR/mediacapture-streams/#device-information-exposure
+  bool DeviceInformationCanBeExposed() const;
+
   nsTHashSet<nsString> mExplicitlyGrantedAudioOutputRawIds;
   nsTArray<RefPtr<Promise>> mPendingEnumerateDevicesPromises;
   // Set only once, if and when required.

modules/libpref/init/StaticPrefList.yaml

@@ -10769,9 +10769,11 @@
 # getUserMedia calls. Should only be turned on to resolve web compat issues,
 # since doing so reveals more user fingerprinting information to trackers.
 #
-# In this mode, camera and microphone device labels are exposed if the site has a
-# persisted permission to either kind, as well as while actively capturing either
-# kind (temporary and tab-specific grace-period permissions do not count).
+# This mode is marginally more permissive than the legacy behavior it attempts
+# to emulate in that device labels do not disappear when tracks are stopped and
+# temporary permission expires. That behavior isn't emulated due to low relative
+# privacy value  compared to spec and it not being being conducive to spec
+# convergence.
 #
 # Planned next steps: true → @IS_NOT_NIGHTLY_BUILD@ → false
 - name: media.devices.enumerate.legacy.enabled