diff --git a/dom/plugins/ipc/PluginModuleChild.cpp b/dom/plugins/ipc/PluginModuleChild.cpp
index e29b13917672..d52c192ca162 100644
--- a/dom/plugins/ipc/PluginModuleChild.cpp
+++ b/dom/plugins/ipc/PluginModuleChild.cpp
@@ -1927,10 +1927,10 @@ NPError PluginModuleChild::PluginRequiresAudioDeviceChanges(
       }
     }
     if (rv == NPERR_NO_ERROR) {
-      mAudioNotificationSet.PutEntry(aInstance);
+      mAudioNotificationSet.Insert(aInstance);
     }
   } else if (!mAudioNotificationSet.IsEmpty()) {
-    mAudioNotificationSet.RemoveEntry(aInstance);
+    mAudioNotificationSet.Remove(aInstance);
     if (mAudioNotificationSet.IsEmpty()) {
       // We released the last plugin.  Unregister from the PluginModuleParent.
       if (!CallNPN_SetValue_NPPVpluginRequiresAudioDeviceChanges(
@@ -1954,9 +1954,7 @@ PluginModuleChild::RecvNPP_SetValue_NPNVaudioDeviceChangeDetails(
   details.flow = detailsIPC.flow;
   details.role = detailsIPC.role;
   details.defaultDevice = detailsIPC.defaultDevice.c_str();
-  for (auto iter = mAudioNotificationSet.ConstIter(); !iter.Done();
-       iter.Next()) {
-    PluginInstanceChild* pluginInst = iter.Get()->GetKey();
+  for (PluginInstanceChild* pluginInst : mAudioNotificationSet) {
     pluginInst->DefaultAudioDeviceChanged(details);
   }
   return IPC_OK();
@@ -1973,9 +1971,7 @@ PluginModuleChild::RecvNPP_SetValue_NPNVaudioDeviceStateChanged(
   NPAudioDeviceStateChanged stateChange;
   stateChange.newState = aDeviceStateIPC.state;
   stateChange.device = aDeviceStateIPC.device.c_str();
-  for (auto iter = mAudioNotificationSet.ConstIter(); !iter.Done();
-       iter.Next()) {
-    PluginInstanceChild* pluginInst = iter.Get()->GetKey();
+  for (PluginInstanceChild* pluginInst : mAudioNotificationSet) {
     pluginInst->AudioDeviceStateChanged(stateChange);
   }
   return IPC_OK();
diff --git a/dom/plugins/ipc/PluginModuleChild.h b/dom/plugins/ipc/PluginModuleChild.h
index 493fe4e7606e..8909ca09a565 100644
--- a/dom/plugins/ipc/PluginModuleChild.h
+++ b/dom/plugins/ipc/PluginModuleChild.h
@@ -19,8 +19,9 @@
 #include "npapi.h"
 #include "npfunctions.h"
 
-#include "nsTHashtable.h"
-#include "nsHashKeys.h"
+#if defined(XP_WIN)
+#  include "nsTHashSet.h"
+#endif
 
 #ifdef MOZ_WIDGET_COCOA
 #  include "PluginInterposeOSX.h"
@@ -282,7 +283,7 @@ class PluginModuleChild : public PPluginModuleChild {
 #endif
 
 #if defined(XP_WIN)
-  typedef nsTHashtable<nsPtrHashKey<PluginInstanceChild>> PluginInstanceSet;
+  typedef nsTHashSet<PluginInstanceChild*> PluginInstanceSet;
   // Set of plugins that have registered to be notified when the audio device
   // changes.
   PluginInstanceSet mAudioNotificationSet;
diff --git a/dom/plugins/ipc/PluginProcessParent.cpp b/dom/plugins/ipc/PluginProcessParent.cpp
index 2f6531126359..8a960ebc966f 100644
--- a/dom/plugins/ipc/PluginProcessParent.cpp
+++ b/dom/plugins/ipc/PluginProcessParent.cpp
@@ -47,7 +47,7 @@ PluginProcessParent::PluginProcessParent(const std::string& aPluginFilePath)
 PluginProcessParent::~PluginProcessParent() {
 #ifdef XP_WIN
   if (sPidSet && mChildPid) {
-    sPidSet->RemoveEntry(mChildPid);
+    sPidSet->Remove(mChildPid);
     if (sPidSet->IsEmpty()) {
       delete sPidSet;
       sPidSet = nullptr;
@@ -165,7 +165,7 @@ void PluginProcessParent::OnChannelConnected(int32_t peer_pid) {
   if (!sPidSet) {
     sPidSet = new PluginProcessParent::PidSet();
   }
-  sPidSet->PutEntry(mChildPid);
+  sPidSet->Insert(mChildPid);
 #endif
 
   GeckoChildProcessHost::OnChannelConnected(peer_pid);
diff --git a/dom/plugins/ipc/PluginProcessParent.h b/dom/plugins/ipc/PluginProcessParent.h
index 48ce24cc7043..b2810865a584 100644
--- a/dom/plugins/ipc/PluginProcessParent.h
+++ b/dom/plugins/ipc/PluginProcessParent.h
@@ -19,8 +19,10 @@
 #include "mozilla/ipc/TaskFactory.h"
 #include "mozilla/UniquePtr.h"
 #include "nsCOMPtr.h"
-#include "nsTHashtable.h"
-#include "nsHashKeys.h"
+
+#if defined(XP_WIN)
+#  include "nsTHashSet.h"
+#endif
 
 namespace mozilla {
 namespace plugins {
@@ -80,7 +82,7 @@ class PluginProcessParent final : public mozilla::ipc::GeckoChildProcessHost {
   UniquePtr<LaunchCompleteTask> mLaunchCompleteTask;
   MessageLoop* mMainMsgLoop;
 #ifdef XP_WIN
-  typedef nsTHashtable<nsUint32HashKey> PidSet;
+  typedef nsTHashSet<uint32_t> PidSet;
   // Set of PIDs for all plugin child processes or NULL if empty.
   static PidSet* sPidSet;
   uint32_t mChildPid;
diff --git a/dom/plugins/ipc/PluginUtilsWin.cpp b/dom/plugins/ipc/PluginUtilsWin.cpp
index 647d0d385e93..c913321d745f 100644
--- a/dom/plugins/ipc/PluginUtilsWin.cpp
+++ b/dom/plugins/ipc/PluginUtilsWin.cpp
@@ -9,13 +9,14 @@
 #include "PluginUtilsWin.h"
 #include "PluginModuleParent.h"
 #include "mozilla/StaticMutex.h"
+#include "nsTHashSet.h"
 
 namespace mozilla {
 namespace plugins {
 namespace PluginUtilsWin {
 
 class AudioNotification;
-typedef nsTHashtable<nsPtrHashKey<PluginModuleParent>> PluginModuleSet;
+typedef nsTHashSet<PluginModuleParent*> PluginModuleSet;
 StaticMutex sMutex;
 
 class AudioDeviceMessageRunnable : public Runnable {
@@ -147,12 +148,12 @@ class AudioNotification final : public IMMNotificationClient {
 
   void AddModule(PluginModuleParent* aModule) {
     StaticMutexAutoLock lock(sMutex);
-    mAudioNotificationSet.PutEntry(aModule);
+    mAudioNotificationSet.Insert(aModule);
   }
 
   void RemoveModule(PluginModuleParent* aModule) {
     StaticMutexAutoLock lock(sMutex);
-    mAudioNotificationSet.RemoveEntry(aModule);
+    mAudioNotificationSet.Remove(aModule);
   }
 
   /*
@@ -247,9 +248,7 @@ AudioDeviceMessageRunnable::Run() {
                     mAudioNotification->GetModuleSet()->Count()));
 
   bool success = true;
-  for (auto iter = mAudioNotification->GetModuleSet()->ConstIter();
-       !iter.Done(); iter.Next()) {
-    PluginModuleParent* pluginModule = iter.Get()->GetKey();
+  for (PluginModuleParent* pluginModule : *mAudioNotification->GetModuleSet()) {
     switch (mMessageType) {
       case DEFAULT_DEVICE_CHANGED:
         success &= pluginModule->SendNPP_SetValue_NPNVaudioDeviceChangeDetails(