--- a/devtools/shared/heapsnapshot/HeapSnapshotTempFileHelperParent.h
+++ b/devtools/shared/heapsnapshot/HeapSnapshotTempFileHelperParent.h
@@ -9,16 +9,18 @@
 
 #include "mozilla/devtools/PHeapSnapshotTempFileHelperParent.h"
 
 namespace mozilla {
 namespace devtools {
 
 class HeapSnapshotTempFileHelperParent
     : public PHeapSnapshotTempFileHelperParent {
+  friend class PHeapSnapshotTempFileHelperParent;
+
   explicit HeapSnapshotTempFileHelperParent() {}
   void ActorDestroy(ActorDestroyReason why) override {}
   mozilla::ipc::IPCResult RecvOpenHeapSnapshotTempFile(
       OpenHeapSnapshotTempFileResponse* outResponse) override;
 
  public:
   static inline PHeapSnapshotTempFileHelperParent* Create();
 };

--- a/dom/cache/CacheChild.h
+++ b/dom/cache/CacheChild.h
@@ -19,16 +19,18 @@ namespace dom {
 class Promise;
 
 namespace cache {
 
 class Cache;
 class CacheOpArgs;
 
 class CacheChild final : public PCacheChild, public ActorChild {
+  friend class PCacheChild;
+
  public:
   class MOZ_RAII AutoLock final {
     CacheChild* mActor;
 
    public:
     explicit AutoLock(CacheChild* aActor) : mActor(aActor) {
       MOZ_DIAGNOSTIC_ASSERT(mActor);
       mActor->Lock();

--- a/dom/cache/CacheOpChild.h
+++ b/dom/cache/CacheOpChild.h
@@ -21,16 +21,17 @@ class Promise;
 
 namespace cache {
 
 class CacheOpChild final : public PCacheOpChild,
                            public ActorChild,
                            public TypeUtils {
   friend class CacheChild;
   friend class CacheStorageChild;
+  friend class PCacheOpChild;
 
  private:
   // This class must be constructed by CacheChild or CacheStorageChild using
   // their ExecuteOp() factory method.
   CacheOpChild(CacheWorkerHolder* aWorkerHolder, nsIGlobalObject* aGlobal,
                nsISupports* aParent, Promise* aPromise);
   ~CacheOpChild();
 

--- a/dom/cache/CacheParent.h
+++ b/dom/cache/CacheParent.h
@@ -12,16 +12,18 @@
 
 namespace mozilla {
 namespace dom {
 namespace cache {
 
 class Manager;
 
 class CacheParent final : public PCacheParent {
+  friend class PCacheParent;
+
  public:
   CacheParent(cache::Manager* aManager, CacheId aCacheId);
   virtual ~CacheParent();
 
  private:
   // PCacheParent methods
   virtual void ActorDestroy(ActorDestroyReason aReason) override;
 

--- a/dom/cache/CacheStorageChild.h
+++ b/dom/cache/CacheStorageChild.h
@@ -21,16 +21,18 @@ class Promise;
 namespace cache {
 
 class CacheOpArgs;
 class CacheStorage;
 class CacheWorkerHolder;
 class PCacheChild;
 
 class CacheStorageChild final : public PCacheStorageChild, public ActorChild {
+  friend class PCacheStorageChild;
+
  public:
   CacheStorageChild(CacheStorage* aListener, CacheWorkerHolder* aWorkerHolder);
   ~CacheStorageChild();
 
   // Must be called by the associated CacheStorage listener in its
   // DestroyInternal() method.  Also, CacheStorage must call
   // SendDestroyFromListener() on the actor in its destructor to trigger
   // ActorDestroy() if it has not been called yet.

--- a/dom/cache/CacheStorageParent.h
+++ b/dom/cache/CacheStorageParent.h
@@ -14,16 +14,18 @@
 namespace mozilla {
 namespace dom {
 namespace cache {
 
 class ManagerId;
 
 class CacheStorageParent final : public PCacheStorageParent,
                                  public PrincipalVerifier::Listener {
+  friend class PCacheStorageParent;
+
  public:
   CacheStorageParent(PBackgroundParent* aManagingActor, Namespace aNamespace,
                      const mozilla::ipc::PrincipalInfo& aPrincipalInfo);
   virtual ~CacheStorageParent();
 
  private:
   // PCacheStorageParent methods
   virtual void ActorDestroy(ActorDestroyReason aReason) override;

--- a/dom/cache/CacheStreamControlChild.h
+++ b/dom/cache/CacheStreamControlChild.h
@@ -19,16 +19,18 @@ class AutoIPCStream;
 namespace dom {
 namespace cache {
 
 class ReadStream;
 
 class CacheStreamControlChild final : public PCacheStreamControlChild,
                                       public StreamControl,
                                       public ActorChild {
+  friend class PCacheStreamControlChild;
+
  public:
   CacheStreamControlChild();
   ~CacheStreamControlChild();
 
   // ActorChild methods
   virtual void StartDestroy() override;
 
   // StreamControl methods

--- a/dom/cache/CacheStreamControlParent.h
+++ b/dom/cache/CacheStreamControlParent.h
@@ -20,16 +20,18 @@ namespace dom {
 namespace cache {
 
 class ReadStream;
 class StreamList;
 
 class CacheStreamControlParent final : public PCacheStreamControlParent,
                                        public StreamControl,
                                        Manager::Listener {
+  friend class PCacheStreamControlParent;
+
  public:
   CacheStreamControlParent();
   ~CacheStreamControlParent();
 
   void SetStreamList(StreamList* aStreamList);
   void Close(const nsID& aId);
   void CloseAll();
   void Shutdown();

--- a/dom/file/ipc/TemporaryIPCBlobChild.h
+++ b/dom/file/ipc/TemporaryIPCBlobChild.h
@@ -20,16 +20,18 @@ class TemporaryIPCBlobChildCallback {
   NS_INLINE_DECL_PURE_VIRTUAL_REFCOUNTING
 
   virtual void OperationSucceeded(BlobImpl* aBlobImpl) = 0;
   virtual void OperationFailed(nsresult aRv) = 0;
 };
 
 class TemporaryIPCBlobChild final
     : public mozilla::ipc::PTemporaryIPCBlobChild {
+  friend class mozilla::ipc::PTemporaryIPCBlobChild;
+
  public:
   NS_INLINE_DECL_REFCOUNTING(TemporaryIPCBlobChild)
 
   explicit TemporaryIPCBlobChild(MutableBlobStorage* aMutableBlobStorage);
 
   void AskForBlob(TemporaryIPCBlobChildCallback* aCallback,
                   const nsACString& aContentType, PRFileDesc* aFD);
 

--- a/dom/file/ipc/TemporaryIPCBlobParent.h
+++ b/dom/file/ipc/TemporaryIPCBlobParent.h
@@ -12,16 +12,18 @@
 
 class nsIFile;
 
 namespace mozilla {
 namespace dom {
 
 class TemporaryIPCBlobParent final
     : public mozilla::ipc::PTemporaryIPCBlobParent {
+  friend class mozilla::ipc::PTemporaryIPCBlobParent;
+
  public:
   explicit TemporaryIPCBlobParent();
 
   mozilla::ipc::IPCResult CreateAndShareFile();
 
  private:
   ~TemporaryIPCBlobParent();
 

--- a/dom/filehandle/ActorsParent.h
+++ b/dom/filehandle/ActorsParent.h
@@ -86,16 +86,18 @@ class FileHandleThreadPool final {
   void Cleanup();
 
   void FinishFileHandle(FileHandle* aFileHandle);
 
   bool MaybeFireCallback(StoragesCompleteCallback* aCallback);
 };
 
 class BackgroundMutableFileParentBase : public PBackgroundMutableFileParent {
+  friend PBackgroundMutableFileParent;
+
   nsTHashtable<nsPtrHashKey<FileHandle>> mFileHandles;
   nsCString mDirectoryId;
   nsString mFileName;
   FileHandleStorage mStorage;
   bool mInvalidated;
   bool mActorWasAlive;
   bool mActorDestroyed;
 

--- a/dom/filesystem/FileSystemTaskBase.h
+++ b/dom/filesystem/FileSystemTaskBase.h
@@ -94,16 +94,18 @@ class FileSystemParams;
  *   function -[GetSuccessRequestResult].
  * Child/Parent:
  *   (7) The process receives IPC and calls [SetRequestResult] to get the
  *   task result. Each task needs to implement its specific success result
  *   parsing function [SetSuccessRequestResult] to get the success result.
  *   (8) Call [HandlerCallback] to send the task result to the content page.
  */
 class FileSystemTaskChildBase : public PFileSystemRequestChild {
+  friend class PFileSystemRequestChild;
+
  public:
   NS_INLINE_DECL_REFCOUNTING(FileSystemTaskChildBase)
 
   /*
    * Start the task. It will dispatch all the information to the parent process,
    * PBackground thread. This method must be called from the owning thread.
    */
   void Start();

--- a/dom/gamepad/ipc/GamepadTestChannelChild.h
+++ b/dom/gamepad/ipc/GamepadTestChannelChild.h
@@ -9,16 +9,18 @@
 
 #ifndef mozilla_dom_GamepadTestChannelChild_h_
 #  define mozilla_dom_GamepadTestChannelChild_h_
 
 namespace mozilla {
 namespace dom {
 
 class GamepadTestChannelChild final : public PGamepadTestChannelChild {
+  friend class PGamepadTestChannelChild;
+
  public:
   GamepadTestChannelChild() {}
   ~GamepadTestChannelChild() {}
   void AddPromise(const uint32_t& aID, Promise* aPromise);
 
  private:
   virtual mozilla::ipc::IPCResult RecvReplyGamepadIndex(
       const uint32_t& aID, const uint32_t& aIndex) override;

--- a/dom/ipc/ContentBridgeChild.h
+++ b/dom/ipc/ContentBridgeChild.h
@@ -10,16 +10,18 @@
 #include "mozilla/dom/PContentBridgeChild.h"
 #include "mozilla/dom/nsIContentChild.h"
 
 namespace mozilla {
 namespace dom {
 
 class ContentBridgeChild final : public PContentBridgeChild,
                                  public nsIContentChild {
+  friend class PContentBridgeChild;
+
  public:
   explicit ContentBridgeChild();
 
   NS_DECL_ISUPPORTS
 
   static void Create(Endpoint<PContentBridgeChild>&& aEndpoint);
 
   virtual void ActorDestroy(ActorDestroyReason aWhy) override;

--- a/dom/ipc/ContentBridgeParent.h
+++ b/dom/ipc/ContentBridgeParent.h
@@ -13,16 +13,18 @@
 #include "nsIObserver.h"
 
 namespace mozilla {
 namespace dom {
 
 class ContentBridgeParent : public PContentBridgeParent,
                             public nsIContentParent,
                             public nsIObserver {
+  friend class PContentBridgeParent;
+
  public:
   explicit ContentBridgeParent();
 
   NS_DECL_ISUPPORTS
   NS_DECL_NSIOBSERVER
 
   virtual void ActorDestroy(ActorDestroyReason aWhy) override;
   void DeferredDestroy();

--- a/dom/ipc/ContentChild.h
+++ b/dom/ipc/ContentChild.h
@@ -80,16 +80,18 @@ class ContentChild final : public PConte
                            public nsIWindowProvider,
                            public nsIContentChild {
   typedef mozilla::dom::ClonedMessageData ClonedMessageData;
   typedef mozilla::ipc::FileDescriptor FileDescriptor;
   typedef mozilla::ipc::OptionalURIParams OptionalURIParams;
   typedef mozilla::ipc::PFileDescriptorSetChild PFileDescriptorSetChild;
   typedef mozilla::ipc::URIParams URIParams;
 
+  friend class PContentChild;
+
  public:
   NS_DECL_NSIWINDOWPROVIDER
 
   ContentChild();
   virtual ~ContentChild();
   NS_IMETHOD QueryInterface(REFNSIID aIID, void** aInstancePtr) override;
   NS_IMETHOD_(MozExternalRefCountType) AddRef(void) override { return 1; }
   NS_IMETHOD_(MozExternalRefCountType) Release(void) override { return 1; }

--- a/dom/ipc/ContentParent.h
+++ b/dom/ipc/ContentParent.h
@@ -119,16 +119,17 @@ class ContentParent final : public PCont
   typedef mozilla::ipc::OptionalURIParams OptionalURIParams;
   typedef mozilla::ipc::PFileDescriptorSetParent PFileDescriptorSetParent;
   typedef mozilla::ipc::TestShellParent TestShellParent;
   typedef mozilla::ipc::URIParams URIParams;
   typedef mozilla::ipc::PrincipalInfo PrincipalInfo;
   typedef mozilla::dom::ClonedMessageData ClonedMessageData;
 
   friend class mozilla::PreallocatedProcessManagerImpl;
+  friend class PContentParent;
 #ifdef FUZZING
   friend class mozilla::ipc::ProtocolFuzzerHelper;
 #endif
 
  public:
   virtual bool IsContentParent() const override { return true; }
 
   using LaunchError = GeckoChildProcessHost::LaunchError;

--- a/dom/ipc/TabChild.h
+++ b/dom/ipc/TabChild.h
@@ -210,16 +210,18 @@ class TabChild final : public TabChildBa
   typedef mozilla::dom::ClonedMessageData ClonedMessageData;
   typedef mozilla::dom::CoalescedMouseData CoalescedMouseData;
   typedef mozilla::dom::CoalescedWheelData CoalescedWheelData;
   typedef mozilla::layers::APZEventState APZEventState;
   typedef mozilla::layers::SetAllowedTouchBehaviorCallback
       SetAllowedTouchBehaviorCallback;
   typedef mozilla::layers::TouchBehaviorFlags TouchBehaviorFlags;
 
+  friend class PBrowserChild;
+
  public:
   /**
    * Find TabChild of aTabId in the same content process of the
    * caller.
    */
   static already_AddRefed<TabChild> FindTabChild(const TabId& aTabId);
 
   // Return a list of all active TabChildren.

--- a/dom/ipc/TabParent.h
+++ b/dom/ipc/TabParent.h
@@ -82,16 +82,18 @@ class TabParent final : public PBrowserP
                         public nsITabParent,
                         public nsIAuthPromptProvider,
                         public nsIKeyEventInPluginCallback,
                         public nsSupportsWeakReference,
                         public TabContext,
                         public LiveResizeListener {
   typedef mozilla::dom::ClonedMessageData ClonedMessageData;
 
+  friend class PBrowserParent;
+
   virtual ~TabParent();
 
  public:
   // Helper class for ContentParent::RecvCreateWindow.
   struct AutoUseNewTab;
 
   // nsITabParent
   NS_DECL_NSITABPARENT

--- a/dom/ipc/WindowGlobalParent.h
+++ b/dom/ipc/WindowGlobalParent.h
@@ -24,16 +24,18 @@ class WindowGlobalChild;
 class JSWindowActorParent;
 
 /**
  * A handle in the parent process to a specific nsGlobalWindowInner object.
  */
 class WindowGlobalParent final : public nsISupports,
                                  public nsWrapperCache,
                                  public PWindowGlobalParent {
+  friend class PWindowGlobalParent;
+
  public:
   NS_DECL_CYCLE_COLLECTING_ISUPPORTS
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS(WindowGlobalParent)
 
   static already_AddRefed<WindowGlobalParent> GetByInnerWindowId(
       uint64_t aInnerWindowId);
 
   static already_AddRefed<WindowGlobalParent> GetByInnerWindowId(

--- a/dom/media/gmp/ChromiumCDMParent.h
+++ b/dom/media/gmp/ChromiumCDMParent.h
@@ -26,16 +26,18 @@ class MediaRawData;
 class ChromiumCDMProxy;
 
 namespace gmp {
 
 class GMPContentParent;
 
 class ChromiumCDMParent final : public PChromiumCDMParent,
                                 public GMPCrashHelperHolder {
+  friend class PChromiumCDMParent;
+
  public:
   typedef MozPromise<bool, MediaResult, /* IsExclusive = */ true> InitPromise;
 
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ChromiumCDMParent)
 
   ChromiumCDMParent(GMPContentParent* aContentParent, uint32_t aPluginId);
 
   uint32_t PluginId() const { return mPluginId; }

--- a/dom/media/gmp/GMPChild.h
+++ b/dom/media/gmp/GMPChild.h
@@ -15,16 +15,18 @@
 #include "prlink.h"
 
 namespace mozilla {
 namespace gmp {
 
 class GMPContentChild;
 
 class GMPChild : public PGMPChild {
+  friend class PGMPChild;
+
  public:
   GMPChild();
   virtual ~GMPChild();
 
   bool Init(const nsAString& aPluginPath, base::ProcessId aParentPid,
             MessageLoop* aIOLoop, IPC::Channel* aChannel);
   MessageLoop* GMPMessageLoop();
 

--- a/dom/media/gmp/GMPContentParent.h
+++ b/dom/media/gmp/GMPContentParent.h
@@ -14,16 +14,18 @@ namespace mozilla {
 namespace gmp {
 
 class GMPParent;
 class GMPVideoDecoderParent;
 class GMPVideoEncoderParent;
 class ChromiumCDMParent;
 
 class GMPContentParent final : public PGMPContentParent, public GMPSharedMem {
+  friend class PGMPContentParent;
+
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(GMPContentParent)
 
   explicit GMPContentParent(GMPParent* aParent = nullptr);
 
   nsresult GetGMPVideoDecoder(GMPVideoDecoderParent** aGMPVD,
                               uint32_t aDecryptorId);
   void VideoDecoderDestroyed(GMPVideoDecoderParent* aDecoder);

--- a/dom/media/gmp/GMPParent.h
+++ b/dom/media/gmp/GMPParent.h
@@ -50,16 +50,18 @@ enum GMPState {
   GMPStateLoaded,
   GMPStateUnloading,
   GMPStateClosing
 };
 
 class GMPContentParent;
 
 class GMPParent final : public PGMPParent {
+  friend class PGMPParent;
+
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(GMPParent)
 
   explicit GMPParent(AbstractThread* aMainThread);
 
   RefPtr<GenericPromise> Init(GeckoMediaPluginServiceParent* aService,
                               nsIFile* aPluginDir);
   nsresult CloneFrom(const GMPParent* aOther);

--- a/dom/media/gmp/GMPStorageChild.h
+++ b/dom/media/gmp/GMPStorageChild.h
@@ -42,16 +42,18 @@ class GMPRecordImpl : public GMPRecord {
  private:
   ~GMPRecordImpl() {}
   const nsCString mName;
   GMPRecordClient* const mClient;
   GMPStorageChild* const mOwner;
 };
 
 class GMPStorageChild : public PGMPStorageChild {
+  friend class PGMPStorageChild;
+
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(GMPStorageChild)
 
   explicit GMPStorageChild(GMPChild* aPlugin);
 
   GMPErr CreateRecord(const nsCString& aRecordName, GMPRecord** aOutRecord,
                       GMPRecordClient* aClient);
 

--- a/dom/media/gmp/GMPStorageParent.h
+++ b/dom/media/gmp/GMPStorageParent.h
@@ -10,16 +10,18 @@
 #include "GMPStorage.h"
 
 namespace mozilla {
 namespace gmp {
 
 class GMPParent;
 
 class GMPStorageParent : public PGMPStorageParent {
+  friend class PGMPStorageParent;
+
  public:
   NS_INLINE_DECL_REFCOUNTING(GMPStorageParent)
   GMPStorageParent(const nsCString& aNodeId, GMPParent* aPlugin);
 
   nsresult Init();
   void Shutdown();
 
  protected:

--- a/dom/media/gmp/GMPTimerChild.h
+++ b/dom/media/gmp/GMPTimerChild.h
@@ -14,16 +14,18 @@
 #include "gmp-platform.h"
 
 namespace mozilla {
 namespace gmp {
 
 class GMPChild;
 
 class GMPTimerChild : public PGMPTimerChild {
+  friend class PGMPTimerChild;
+
  public:
   NS_INLINE_DECL_REFCOUNTING(GMPTimerChild)
 
   explicit GMPTimerChild(GMPChild* aPlugin);
 
   GMPErr SetTimer(GMPTask* aTask, int64_t aTimeoutMS);
 
  protected:

--- a/dom/media/gmp/GMPTimerParent.h
+++ b/dom/media/gmp/GMPTimerParent.h
@@ -13,16 +13,18 @@
 #include "nsHashKeys.h"
 #include "mozilla/Monitor.h"
 #include "nsIThread.h"
 
 namespace mozilla {
 namespace gmp {
 
 class GMPTimerParent : public PGMPTimerParent {
+  friend class PGMPTimerParent;
+
  public:
   NS_INLINE_DECL_REFCOUNTING(GMPTimerParent)
   explicit GMPTimerParent(nsISerialEventTarget* aGMPEventTarget);
 
   void Shutdown();
 
  protected:
   mozilla::ipc::IPCResult RecvSetTimer(const uint32_t& aTimerId,

--- a/dom/media/gmp/GMPVideoDecoderChild.h
+++ b/dom/media/gmp/GMPVideoDecoderChild.h
@@ -16,16 +16,18 @@
 namespace mozilla {
 namespace gmp {
 
 class GMPContentChild;
 
 class GMPVideoDecoderChild : public PGMPVideoDecoderChild,
                              public GMPVideoDecoderCallback,
                              public GMPSharedMemManager {
+  friend class PGMPVideoDecoderChild;
+
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(GMPVideoDecoderChild);
 
   explicit GMPVideoDecoderChild(GMPContentChild* aPlugin);
 
   void Init(GMPVideoDecoder* aDecoder);
   GMPVideoHostImpl& Host();
 

--- a/dom/media/gmp/GMPVideoDecoderParent.h
+++ b/dom/media/gmp/GMPVideoDecoderParent.h
@@ -21,16 +21,18 @@ namespace mozilla {
 namespace gmp {
 
 class GMPContentParent;
 
 class GMPVideoDecoderParent final : public PGMPVideoDecoderParent,
                                     public GMPVideoDecoderProxy,
                                     public GMPSharedMemManager,
                                     public GMPCrashHelperHolder {
+  friend class PGMPVideoDecoderParent;
+
  public:
   NS_INLINE_DECL_REFCOUNTING(GMPVideoDecoderParent)
 
   explicit GMPVideoDecoderParent(GMPContentParent* aPlugin);
 
   GMPVideoHostImpl& Host();
   nsresult Shutdown();
 

--- a/dom/media/gmp/GMPVideoEncoderChild.h
+++ b/dom/media/gmp/GMPVideoEncoderChild.h
@@ -15,16 +15,18 @@
 namespace mozilla {
 namespace gmp {
 
 class GMPContentChild;
 
 class GMPVideoEncoderChild : public PGMPVideoEncoderChild,
                              public GMPVideoEncoderCallback,
                              public GMPSharedMemManager {
+  friend class PGMPVideoEncoderChild;
+
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(GMPVideoEncoderChild);
 
   explicit GMPVideoEncoderChild(GMPContentChild* aPlugin);
 
   void Init(GMPVideoEncoder* aEncoder);
   GMPVideoHostImpl& Host();
 

--- a/dom/media/gmp/GMPVideoEncoderParent.h
+++ b/dom/media/gmp/GMPVideoEncoderParent.h
@@ -20,16 +20,18 @@ namespace mozilla {
 namespace gmp {
 
 class GMPContentParent;
 
 class GMPVideoEncoderParent : public GMPVideoEncoderProxy,
                               public PGMPVideoEncoderParent,
                               public GMPSharedMemManager,
                               public GMPCrashHelperHolder {
+  friend class PGMPVideoEncoderParent;
+
  public:
   NS_INLINE_DECL_REFCOUNTING(GMPVideoEncoderParent)
 
   explicit GMPVideoEncoderParent(GMPContentParent* aPlugin);
 
   GMPVideoHostImpl& Host();
   void Shutdown();
 

--- a/dom/media/ipc/RemoteDecoderManagerChild.h
+++ b/dom/media/ipc/RemoteDecoderManagerChild.h
@@ -5,16 +5,18 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #ifndef include_dom_media_ipc_RemoteDecoderManagerChild_h
 #define include_dom_media_ipc_RemoteDecoderManagerChild_h
 #include "mozilla/PRemoteDecoderManagerChild.h"
 
 namespace mozilla {
 
 class RemoteDecoderManagerChild final : public PRemoteDecoderManagerChild {
+  friend class PRemoteDecoderManagerChild;
+
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(RemoteDecoderManagerChild)
 
   // Can only be called from the manager thread
   static RemoteDecoderManagerChild* GetSingleton();
 
   // Can be called from any thread.
   static nsIThread* GetManagerThread();

--- a/dom/media/ipc/RemoteDecoderManagerParent.h
+++ b/dom/media/ipc/RemoteDecoderManagerParent.h
@@ -7,16 +7,18 @@
 #define include_dom_media_ipc_RemoteDecoderManagerParent_h
 #include "mozilla/PRemoteDecoderManagerParent.h"
 
 namespace mozilla {
 
 class RemoteDecoderManagerThreadHolder;
 
 class RemoteDecoderManagerParent final : public PRemoteDecoderManagerParent {
+  friend class PRemoteDecoderManagerParent;
+
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(RemoteDecoderManagerParent)
 
   static bool CreateForContent(
       Endpoint<PRemoteDecoderManagerParent>&& aEndpoint);
 
   static bool StartupThreads();
   static void ShutdownThreads();

--- a/dom/media/ipc/VideoDecoderManagerChild.h
+++ b/dom/media/ipc/VideoDecoderManagerChild.h
@@ -11,16 +11,18 @@
 
 namespace mozilla {
 namespace gfx {
 class SourceSurface;
 }
 
 class VideoDecoderManagerChild final : public PVideoDecoderManagerChild,
                                        public mozilla::ipc::IShmemAllocator {
+  friend class PVideoDecoderManagerChild;
+
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(VideoDecoderManagerChild)
 
   // Can only be called from the manager thread
   static VideoDecoderManagerChild* GetSingleton();
 
   // Can be called from any thread.
   static nsIThread* GetManagerThread();

--- a/dom/media/ipc/VideoDecoderManagerParent.h
+++ b/dom/media/ipc/VideoDecoderManagerParent.h
@@ -8,16 +8,18 @@
 
 #include "mozilla/PVideoDecoderManagerParent.h"
 
 namespace mozilla {
 
 class VideoDecoderManagerThreadHolder;
 
 class VideoDecoderManagerParent final : public PVideoDecoderManagerParent {
+  friend class PVideoDecoderManagerParent;
+
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(VideoDecoderManagerParent)
 
   static bool CreateForContent(
       Endpoint<PVideoDecoderManagerParent>&& aEndpoint);
 
   // Can be called from any thread
   SurfaceDescriptorGPUVideo StoreImage(layers::Image* aImage,

--- a/dom/media/systemservices/MediaSystemResourceManagerChild.h
+++ b/dom/media/systemservices/MediaSystemResourceManagerChild.h
@@ -19,16 +19,18 @@ class BackgroundChildImpl;
 
 namespace media {
 
 /**
  * Handle MediaSystemResourceManager's IPC
  */
 class MediaSystemResourceManagerChild final
     : public PMediaSystemResourceManagerChild {
+  friend class PMediaSystemResourceManagerChild;
+
  public:
   struct ResourceListener {
     /* The resource is reserved and can be granted.
      * The client can allocate the requested resource.
      */
     virtual void resourceReserved() = 0;
     /* The resource is not reserved any more.
      * The client should release the resource as soon as possible if the

--- a/dom/media/systemservices/MediaSystemResourceManagerParent.h
+++ b/dom/media/systemservices/MediaSystemResourceManagerParent.h
@@ -14,16 +14,18 @@
 namespace mozilla {
 namespace media {
 
 /**
  * Handle MediaSystemResourceManager's IPC
  */
 class MediaSystemResourceManagerParent final
     : public PMediaSystemResourceManagerParent {
+  friend class PMediaSystemResourceManagerParent;
+
  public:
   MediaSystemResourceManagerParent();
   virtual ~MediaSystemResourceManagerParent();
 
  protected:
   mozilla::ipc::IPCResult RecvAcquire(
       const uint32_t& aId, const MediaSystemResourceType& aResourceType,
       const bool& aWillWait) override;

--- a/dom/media/webspeech/synth/ipc/SpeechSynthesisChild.h
+++ b/dom/media/webspeech/synth/ipc/SpeechSynthesisChild.h
@@ -14,16 +14,17 @@ namespace mozilla {
 namespace dom {
 
 class nsSynthVoiceRegistry;
 class SpeechSynthesisRequestChild;
 class SpeechTaskChild;
 
 class SpeechSynthesisChild : public PSpeechSynthesisChild {
   friend class nsSynthVoiceRegistry;
+  friend class PSpeechSynthesisChild;
 
  public:
   mozilla::ipc::IPCResult RecvInitialVoicesAndState(
       nsTArray<RemoteVoice>&& aVoices, nsTArray<nsString>&& aDefaults,
       const bool& aIsSpeaking) override;
 
   mozilla::ipc::IPCResult RecvVoiceAdded(const RemoteVoice& aVoice) override;
 

--- a/dom/media/webspeech/synth/ipc/SpeechSynthesisParent.h
+++ b/dom/media/webspeech/synth/ipc/SpeechSynthesisParent.h
@@ -14,16 +14,17 @@ namespace dom {
 
 class ContentParent;
 class SpeechTaskParent;
 class SpeechSynthesisRequestParent;
 
 class SpeechSynthesisParent : public PSpeechSynthesisParent {
   friend class ContentParent;
   friend class SpeechSynthesisRequestParent;
+  friend class PSpeechSynthesisParent;
 
  public:
   void ActorDestroy(ActorDestroyReason aWhy) override;
 
   bool SendInit();
 
  protected:
   SpeechSynthesisParent();

--- a/dom/messagechannel/MessagePortChild.h
+++ b/dom/messagechannel/MessagePortChild.h
@@ -12,16 +12,18 @@
 #include "nsISupportsImpl.h"
 
 namespace mozilla {
 namespace dom {
 
 class MessagePort;
 
 class MessagePortChild final : public PMessagePortChild {
+  friend class PMessagePortChild;
+
  public:
   NS_INLINE_DECL_REFCOUNTING(MessagePortChild)
 
   MessagePortChild();
 
   void SetPort(MessagePort* aPort) { mPort = aPort; }
 
  private:

--- a/dom/messagechannel/MessagePortParent.h
+++ b/dom/messagechannel/MessagePortParent.h
@@ -10,16 +10,18 @@
 #include "mozilla/dom/PMessagePortParent.h"
 
 namespace mozilla {
 namespace dom {
 
 class MessagePortService;
 
 class MessagePortParent final : public PMessagePortParent {
+  friend class PMessagePortParent;
+
  public:
   explicit MessagePortParent(const nsID& aUUID);
   ~MessagePortParent();
 
   bool Entangle(const nsID& aDestinationUUID, const uint32_t& aSequenceID);
 
   bool Entangled(const nsTArray<ClonedMessageData>& aMessages);
 

--- a/dom/payments/ipc/PaymentRequestChild.h
+++ b/dom/payments/ipc/PaymentRequestChild.h
@@ -10,16 +10,18 @@
 #include "mozilla/dom/PPaymentRequestChild.h"
 
 namespace mozilla {
 namespace dom {
 
 class PaymentRequest;
 
 class PaymentRequestChild final : public PPaymentRequestChild {
+  friend class PPaymentRequestChild;
+
  public:
   explicit PaymentRequestChild(PaymentRequest* aRequest);
 
   void MaybeDelete(bool aCanBeInManager);
 
   nsresult RequestPayment(const IPCPaymentActionRequest& aAction);
 
  protected:

--- a/dom/payments/ipc/PaymentRequestParent.h
+++ b/dom/payments/ipc/PaymentRequestParent.h
@@ -10,16 +10,18 @@
 #include "mozilla/dom/PPaymentRequestParent.h"
 #include "nsIPaymentAddress.h"
 #include "nsIPaymentActionResponse.h"
 
 namespace mozilla {
 namespace dom {
 
 class PaymentRequestParent final : public PPaymentRequestParent {
+  friend class PPaymentRequestParent;
+
   NS_INLINE_DECL_REFCOUNTING(PaymentRequestParent)
  public:
   PaymentRequestParent();
 
   nsresult RespondPayment(nsIPaymentActionResponse* aResponse);
   nsresult ChangeShippingAddress(const nsAString& aRequestId,
                                  nsIPaymentAddress* aAddress);
   nsresult ChangeShippingOption(const nsAString& aRequestId,

--- a/dom/plugins/ipc/PluginInstanceChild.h
+++ b/dom/plugins/ipc/PluginInstanceChild.h
@@ -47,16 +47,17 @@ class PBrowserStreamChild;
 class BrowserStreamChild;
 class StreamNotifyChild;
 
 class PluginInstanceChild : public PPluginInstanceChild {
   friend class BrowserStreamChild;
   friend class PluginStreamChild;
   friend class StreamNotifyChild;
   friend class PluginScriptableObjectChild;
+  friend class PPluginInstanceChild;
 
 #ifdef OS_WIN
   friend LRESULT CALLBACK PluginWindowProc(HWND hWnd, UINT message,
                                            WPARAM wParam, LPARAM lParam);
   static LRESULT CALLBACK PluginWindowProcInternal(HWND hWnd, UINT message,
                                                    WPARAM wParam,
                                                    LPARAM lParam);
 #endif

--- a/dom/plugins/ipc/PluginInstanceParent.h
+++ b/dom/plugins/ipc/PluginInstanceParent.h
@@ -40,16 +40,17 @@ namespace plugins {
 class PBrowserStreamParent;
 class PluginModuleParent;
 class D3D11SurfaceHolder;
 
 class PluginInstanceParent : public PPluginInstanceParent {
   friend class PluginModuleParent;
   friend class BrowserStreamParent;
   friend class StreamNotifyParent;
+  friend class PPluginInstanceParent;
 
 #if defined(XP_WIN)
  public:
   /**
    * Helper method for looking up instances based on a supplied id.
    */
   static PluginInstanceParent* LookupPluginInstanceByID(uintptr_t aId);
 #endif  // defined(XP_WIN)

--- a/dom/plugins/ipc/PluginModuleChild.h
+++ b/dom/plugins/ipc/PluginModuleChild.h
@@ -36,16 +36,18 @@ namespace mozilla {
 
 class ChildProfilerController;
 
 namespace plugins {
 
 class PluginInstanceChild;
 
 class PluginModuleChild : public PPluginModuleChild {
+  friend class PPluginModuleChild;
+
  protected:
   virtual mozilla::ipc::RacyInterruptPolicy MediateInterruptRace(
       const MessageInfo& parent, const MessageInfo& child) override {
     return MediateRace(parent, child);
   }
 
   virtual bool ShouldContinueFromReplyTimeout() override;
 

--- a/dom/plugins/ipc/PluginModuleParent.h
+++ b/dom/plugins/ipc/PluginModuleParent.h
@@ -72,16 +72,18 @@ class FinishInjectorInitTask;
  */
 class PluginModuleParent : public PPluginModuleParent,
                            public PluginLibrary
 #ifdef MOZ_CRASHREPORTER_INJECTOR
     ,
                            public CrashReporter::InjectorCrashCallback
 #endif
 {
+  friend class PPluginModuleParent;
+
  protected:
   typedef mozilla::PluginLibrary PluginLibrary;
 
   PPluginInstanceParent* AllocPPluginInstanceParent(
       const nsCString& aMimeType, const InfallibleTArray<nsCString>& aNames,
       const InfallibleTArray<nsCString>& aValues) override;
 
   virtual bool DeallocPPluginInstanceParent(

--- a/dom/plugins/ipc/StreamNotifyChild.h
+++ b/dom/plugins/ipc/StreamNotifyChild.h
@@ -12,16 +12,17 @@
 namespace mozilla {
 namespace plugins {
 
 class BrowserStreamChild;
 
 class StreamNotifyChild : public PStreamNotifyChild {
   friend class PluginInstanceChild;
   friend class BrowserStreamChild;
+  friend class PStreamNotifyChild;
 
  public:
   explicit StreamNotifyChild(const nsCString& aURL)
       : mURL(aURL), mClosure(nullptr), mBrowserStream(nullptr) {}
 
   virtual void ActorDestroy(ActorDestroyReason why) override;
 
   void SetValid(void* aClosure) { mClosure = aClosure; }

--- a/dom/plugins/ipc/StreamNotifyParent.h
+++ b/dom/plugins/ipc/StreamNotifyParent.h
@@ -9,16 +9,17 @@
 
 #include "mozilla/plugins/PStreamNotifyParent.h"
 
 namespace mozilla {
 namespace plugins {
 
 class StreamNotifyParent : public PStreamNotifyParent {
   friend class PluginInstanceParent;
+  friend class PStreamNotifyParent;
 
   StreamNotifyParent() : mDestructionFlag(nullptr) {}
   ~StreamNotifyParent() {
     if (mDestructionFlag) *mDestructionFlag = true;
   }
 
  public:
   // If we are destroyed within the call to NPN_GetURLNotify, notify the caller

--- a/dom/serviceworkers/ServiceWorkerManagerParent.h
+++ b/dom/serviceworkers/ServiceWorkerManagerParent.h
@@ -18,16 +18,17 @@ class BackgroundParentImpl;
 }  // namespace ipc
 
 namespace dom {
 
 class ServiceWorkerManagerService;
 
 class ServiceWorkerManagerParent final : public PServiceWorkerManagerParent {
   friend class mozilla::ipc::BackgroundParentImpl;
+  friend class PServiceWorkerManagerParent;
 
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(ServiceWorkerManagerParent)
 
   uint64_t ID() const { return mID; }
 
  private:
   ServiceWorkerManagerParent();

--- a/dom/workers/remoteworkers/RemoteWorkerChild.h
+++ b/dom/workers/remoteworkers/RemoteWorkerChild.h
@@ -18,16 +18,18 @@ namespace dom {
 
 class RemoteWorkerData;
 class WeakWorkerRef;
 class WorkerErrorReport;
 class WorkerPrivate;
 class OptionalMessagePortIdentifier;
 
 class RemoteWorkerChild final : public PRemoteWorkerChild {
+  friend class PRemoteWorkerChild;
+
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(RemoteWorkerChild)
 
   RemoteWorkerChild();
 
   void ExecWorker(const RemoteWorkerData& aData);
 
   void InitializeOnWorker(WorkerPrivate* aWorkerPrivate);

--- a/dom/workers/remoteworkers/RemoteWorkerParent.h
+++ b/dom/workers/remoteworkers/RemoteWorkerParent.h
@@ -10,16 +10,18 @@
 #include "mozilla/dom/PRemoteWorkerParent.h"
 
 namespace mozilla {
 namespace dom {
 
 class RemoteWorkerController;
 
 class RemoteWorkerParent final : public PRemoteWorkerParent {
+  friend class PRemoteWorkerParent;
+
  public:
   NS_INLINE_DECL_REFCOUNTING(RemoteWorkerParent)
 
   RemoteWorkerParent();
 
   void Initialize();
 
   void SetController(RemoteWorkerController* aController);

--- a/dom/workers/sharedworkers/SharedWorkerChild.h
+++ b/dom/workers/sharedworkers/SharedWorkerChild.h
@@ -11,16 +11,18 @@
 #include "nsISupportsImpl.h"
 
 namespace mozilla {
 namespace dom {
 
 class SharedWorker;
 
 class SharedWorkerChild final : public mozilla::dom::PSharedWorkerChild {
+  friend class PSharedWorkerChild;
+
  public:
   NS_INLINE_DECL_REFCOUNTING(SharedWorkerChild)
 
   SharedWorkerChild();
 
   void SetParent(SharedWorker* aSharedWorker) { mParent = aSharedWorker; }
 
   void SendClose();

--- a/gfx/layers/ipc/APZCTreeManagerChild.h
+++ b/gfx/layers/ipc/APZCTreeManagerChild.h
@@ -14,16 +14,18 @@
 namespace mozilla {
 namespace layers {
 
 class APZInputBridgeChild;
 class RemoteCompositorSession;
 
 class APZCTreeManagerChild : public IAPZCTreeManager,
                              public PAPZCTreeManagerChild {
+  friend class PAPZCTreeManagerChild;
+
  public:
   APZCTreeManagerChild();
 
   void SetCompositorSession(RemoteCompositorSession* aSession);
   void SetInputBridge(APZInputBridgeChild* aInputBridge);
   void Destroy();
 
   void SetKeyboardMap(const KeyboardMap& aKeyboardMap) override;

--- a/gfx/layers/ipc/CompositorBridgeChild.h
+++ b/gfx/layers/ipc/CompositorBridgeChild.h
@@ -48,16 +48,18 @@ class CompositorOptions;
 class TextureClient;
 class TextureClientPool;
 struct FrameMetrics;
 
 class CompositorBridgeChild final : public PCompositorBridgeChild,
                                     public TextureForwarder {
   typedef InfallibleTArray<AsyncParentMessageData> AsyncParentMessageArray;
 
+  friend class PCompositorBridgeChild;
+
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(CompositorBridgeChild, override);
 
   explicit CompositorBridgeChild(CompositorManagerChild* aManager);
 
   /**
    * Initialize the singleton compositor bridge for a content process.
    */

--- a/gfx/layers/ipc/CompositorBridgeParent.h
+++ b/gfx/layers/ipc/CompositorBridgeParent.h
@@ -208,16 +208,17 @@ MOZ_MAKE_ENUM_CLASS_BITWISE_OPERATORS(
 
 class CompositorBridgeParent final : public CompositorBridgeParentBase,
                                      public CompositorController,
                                      public CompositorVsyncSchedulerOwner {
   friend class CompositorThreadHolder;
   friend class InProcessCompositorSession;
   friend class gfx::GPUProcessManager;
   friend class gfx::GPUParent;
+  friend class PCompositorBridgeParent;
 #ifdef FUZZING
   friend class mozilla::ipc::ProtocolFuzzerHelper;
 #endif
 
  public:
   NS_IMETHOD_(MozExternalRefCountType) AddRef() override {
     return CompositorBridgeParentBase::AddRef();
   }

--- a/gfx/layers/ipc/LayerTransactionParent.h
+++ b/gfx/layers/ipc/LayerTransactionParent.h
@@ -33,16 +33,18 @@ class CompositorBridgeParentBase;
 
 class LayerTransactionParent final : public PLayerTransactionParent,
                                      public CompositableParentManager,
                                      public ShmemAllocator {
   typedef InfallibleTArray<Edit> EditArray;
   typedef InfallibleTArray<OpDestroy> OpDestroyArray;
   typedef InfallibleTArray<PluginWindowData> PluginsArray;
 
+  friend class PLayerTransactionParent;
+
  public:
   LayerTransactionParent(HostLayerManager* aManager,
                          CompositorBridgeParentBase* aBridge,
                          CompositorAnimationStorage* aAnimStorage, LayersId aId,
                          TimeDuration aVsyncRate);
 
  protected:
   ~LayerTransactionParent();

--- a/gfx/layers/ipc/UiCompositorControllerChild.h
+++ b/gfx/layers/ipc/UiCompositorControllerChild.h
@@ -17,16 +17,18 @@
 
 class nsBaseWidget;
 
 namespace mozilla {
 namespace layers {
 
 class UiCompositorControllerChild final
     : protected PUiCompositorControllerChild {
+  friend class PUiCompositorControllerChild;
+
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(UiCompositorControllerChild)
 
   static RefPtr<UiCompositorControllerChild> CreateForSameProcess(
       const LayersId& aRootLayerTreeId);
   static RefPtr<UiCompositorControllerChild> CreateForGPUProcess(
       const uint64_t& aProcessToken,
       Endpoint<PUiCompositorControllerChild>&& aEndpoint);

--- a/gfx/layers/wr/WebRenderBridgeChild.h
+++ b/gfx/layers/wr/WebRenderBridgeChild.h
@@ -54,16 +54,18 @@ class ThreadSafeWeakPtrHashKey : public 
 
 typedef ThreadSafeWeakPtrHashKey<gfx::UnscaledFont> UnscaledFontHashKey;
 typedef ThreadSafeWeakPtrHashKey<gfx::ScaledFont> ScaledFontHashKey;
 
 class WebRenderBridgeChild final : public PWebRenderBridgeChild,
                                    public CompositableForwarder {
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(WebRenderBridgeChild, override)
 
+  friend class PWebRenderBridgeChild;
+
  public:
   explicit WebRenderBridgeChild(const wr::PipelineId& aPipelineId);
 
   void AddWebRenderParentCommand(const WebRenderParentCommand& aCmd);
 
   void UpdateResources(wr::IpcResourceUpdateQueue& aResources);
   void BeginTransaction();
   void EndTransaction(const wr::LayoutSize& aContentSize,

--- a/gfx/vr/ipc/VRChild.h
+++ b/gfx/vr/ipc/VRChild.h
@@ -17,16 +17,18 @@ namespace ipc {
 class CrashReporterHost;
 }  // namespace ipc
 namespace gfx {
 
 class VRProcessParent;
 class VRChild;
 
 class VRChild final : public PVRChild, public gfxVarReceiver {
+  friend class PVRChild;
+
  public:
   explicit VRChild(VRProcessParent* aHost);
   ~VRChild() = default;
 
   static void Destroy(UniquePtr<VRChild>&& aChild);
   void Init();
   virtual void OnVarChanged(const GfxVarUpdate& aVar) override;
 
@@ -42,9 +44,9 @@ class VRChild final : public PVRChild, p
  private:
   VRProcessParent* mHost;
   UniquePtr<ipc::CrashReporterHost> mCrashReporter;
 };
 
 }  // namespace gfx
 }  // namespace mozilla
 
-#endif  // GFX_VR_CHILD_H
\ No newline at end of file
+#endif  // GFX_VR_CHILD_H

--- a/gfx/vr/ipc/VRGPUParent.h
+++ b/gfx/vr/ipc/VRGPUParent.h
@@ -11,16 +11,18 @@
 #include "VRService.h"
 
 namespace mozilla {
 namespace gfx {
 
 class VRGPUParent final : public PVRGPUParent {
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(VRGPUParent)
 
+  friend class PVRGPUParent;
+
  public:
   static RefPtr<VRGPUParent> CreateForGPU(Endpoint<PVRGPUParent>&& aEndpoint);
   virtual void ActorDestroy(ActorDestroyReason aWhy) override;
   bool IsClosed();
 
  protected:
   void Bind(Endpoint<PVRGPUParent>&& aEndpoint);
   virtual mozilla::ipc::IPCResult RecvStartVRService() override;

--- a/gfx/vr/ipc/VRManagerChild.h
+++ b/gfx/vr/ipc/VRManagerChild.h
@@ -27,16 +27,18 @@ class VRMockDisplay;
 namespace layers {
 class SyncObjectClient;
 }
 namespace gfx {
 class VRLayerChild;
 class VRDisplayClient;
 
 class VRManagerChild : public PVRManagerChild {
+  friend class PVRManagerChild;
+
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(VRManagerChild);
 
   static VRManagerChild* Get();
 
   // Indicate that an observer wants to receive VR events.
   void AddListener(dom::VREventObserver* aObserver);
   // Indicate that an observer should no longer receive VR events.

--- a/gfx/vr/ipc/VRManagerParent.h
+++ b/gfx/vr/ipc/VRManagerParent.h
@@ -24,16 +24,18 @@ class VRManager;
 namespace impl {
 class VRDisplayPuppet;
 class VRControllerPuppet;
 }  // namespace impl
 
 class VRManagerParent final : public PVRManagerParent {
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(VRManagerParent);
 
+  friend class PVRManagerParent;
+
  public:
   explicit VRManagerParent(ProcessId aChildProcessId, bool aIsContentChild);
 
   static VRManagerParent* CreateSameProcess();
   static bool CreateForGPUProcess(Endpoint<PVRManagerParent>&& aEndpoint);
   static bool CreateForContent(Endpoint<PVRManagerParent>&& aEndpoint);
 
   bool IsSameProcess() const;

--- a/gfx/vr/ipc/VRParent.h
+++ b/gfx/vr/ipc/VRParent.h
@@ -14,16 +14,18 @@ namespace mozilla {
 namespace gfx {
 
 class VRService;
 class VRSystemManagerExternal;
 
 class VRParent final : public PVRParent {
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(VRParent);
 
+  friend class PVRParent;
+
  public:
   explicit VRParent();
 
   bool Init(base::ProcessId aParentPid, const char* aParentBuildID,
             MessageLoop* aIOLoop, IPC::Channel* aChannel);
   virtual void ActorDestroy(ActorDestroyReason aWhy) override;
   bool GetOpenVRControllerActionPath(nsCString* aPath);
   bool GetOpenVRControllerManifestPath(OpenVRControllerType aType,
@@ -53,9 +55,9 @@ class VRParent final : public PVRParent 
   nsDataHashtable<nsUint32HashKey, nsCString> mOpenVRControllerManifest;
   RefPtr<VRGPUParent> mVRGPUParent;
   DISALLOW_COPY_AND_ASSIGN(VRParent);
 };
 
 }  // namespace gfx
 }  // namespace mozilla
 
-#endif  // GFX_VR_PARENT_H
\ No newline at end of file
+#endif  // GFX_VR_PARENT_H

--- a/ipc/glue/FileDescriptorSetChild.h
+++ b/ipc/glue/FileDescriptorSetChild.h
@@ -23,16 +23,17 @@ class nsIContentChild;
 namespace ipc {
 
 class BackgroundChildImpl;
 class FileDescriptor;
 
 class FileDescriptorSetChild final : public PFileDescriptorSetChild {
   friend class BackgroundChildImpl;
   friend class mozilla::dom::nsIContentChild;
+  friend class PFileDescriptorSetChild;
 
   nsTArray<FileDescriptor> mFileDescriptors;
 
  public:
   void ForgetFileDescriptors(nsTArray<FileDescriptor>& aFileDescriptors);
 
  private:
   explicit FileDescriptorSetChild(const FileDescriptor& aFileDescriptor);

--- a/ipc/glue/FileDescriptorSetParent.h
+++ b/ipc/glue/FileDescriptorSetParent.h
@@ -23,16 +23,17 @@ class nsIContentParent;
 namespace ipc {
 
 class BackgroundParentImpl;
 class FileDescriptor;
 
 class FileDescriptorSetParent final : public PFileDescriptorSetParent {
   friend class BackgroundParentImpl;
   friend class mozilla::dom::nsIContentParent;
+  friend class PFileDescriptorSetParent;
 
   nsTArray<FileDescriptor> mFileDescriptors;
 
  public:
   void ForgetFileDescriptors(nsTArray<FileDescriptor>& aFileDescriptors);
 
  private:
   explicit FileDescriptorSetParent(const FileDescriptor& aFileDescriptor);

--- a/ipc/glue/InProcessChild.h
+++ b/ipc/glue/InProcessChild.h
@@ -26,16 +26,17 @@ class InProcessParent;
  *
  * The `PInProcess` actor should be used as an alternate manager to `PContent`
  * for async actors which want to communicate uniformly between Content->Chrome
  * and Chrome->Chrome situations.
  */
 class InProcessChild : public PInProcessChild {
  public:
   friend class InProcessParent;
+  friend class PInProcessChild;
 
   NS_INLINE_DECL_REFCOUNTING(InProcessChild)
 
   // Get the singleton instance of this actor.
   static InProcessChild* Singleton();
 
   // Get the parent side of the in-process child actor |aActor|. If |aActor| is
   // not an in-process actor, or is not connected, this method will return

--- a/ipc/glue/InProcessParent.h
+++ b/ipc/glue/InProcessParent.h
@@ -26,16 +26,17 @@ class InProcessChild;
  *
  * The `PInProcess` actor should be used as an alternate manager to `PContent`
  * for async actors which want to communicate uniformly between Content->Chrome
  * and Chrome->Chrome situations.
  */
 class InProcessParent : public nsIObserver, public PInProcessParent {
  public:
   friend class InProcessChild;
+  friend class PInProcessParent;
 
   NS_DECL_ISUPPORTS
   NS_DECL_NSIOBSERVER
 
   // Get the singleton instance of this actor.
   static InProcessParent* Singleton();
 
   // Get the child side of the in-process child actor |aActor|. If |aActor| is

new file mode 100644
--- /dev/null
+++ b/ipc/ipdl/ipdl/direct_call.py
@@ -0,0 +1,329 @@
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+# Our long term goal is to burn this list down, so new entries should be added
+# extremely sparingly and only with a very good reason! You must have an IPC
+# peer's r+ to add something new!
+
+# {(Protocol, side): (Class, HeaderFile)}
+DIRECT_CALL_OVERRIDES = {
+    ("PAPZ", "parent"): (
+        "RemoteContentController", "mozilla/layers/RemoteContentController.h"
+    ),
+
+    ("PBackgroundMutableFile", "parent"): (
+        "BackgroundMutableFileParentBase", "mozilla/dom/filehandle/ActorsParent.h"
+    ),
+
+    ("PBrowser", "parent"): ("TabParent", "mozilla/dom/TabParent.h"),
+
+    ("PChromiumCDM", "parent"): ("ChromiumCDMParent", "ChromiumCDMParent.h"),
+
+    ("PCompositorBridge", "parent"): (
+        "CompositorBridgeParentBase", "mozilla/layers/CompositorBridgeParent.h"
+    ),
+
+    ("PContentPermissionRequest", "child"): (
+        "RemotePermissionRequest", "nsContentPermissionHelper.h"
+    ),
+
+    ("PFileSystemRequest", "child"): (
+        "FileSystemTaskChildBase", "mozilla/dom/FileSystemTaskBase.h"
+    ),
+
+    ("PGMP", "child"): ("GMPChild", "GMPChild.h"),
+    ("PGMP", "parent"): ("GMPParent", "GMPParent.h"),
+    ("PGMPContent", "child"): ("GMPContentChild", "GMPContentChild.h"),
+    ("PGMPStorage", "child"): ("GMPStorageChild", "GMPStorageChild.h"),
+    ("PGMPTimer", "child"): ("GMPTimerChild", "GMPTimerChild.h"),
+    ("PGMPTimer", "parent"): ("GMPTimerParent", "GMPTimerParent.h"),
+    ("PGMPVideoEncoder", "child"): ("GMPVideoEncoderChild", "GMPVideoEncoderChild.h"),
+    ("PGMPVideoDecoder", "child"): ("GMPVideoDecoderChild", "GMPVideoDecoderChild.h"),
+
+    ("PIPCBlobInputStream", "child"): (
+        "mozilla::dom::IPCBlobInputStreamChild", "mozilla/dom/ipc/IPCBlobInputStreamChild.h"
+    ),
+    ("PIPCBlobInputStream", "parent"): (
+        "mozilla::dom::IPCBlobInputStreamParent", "mozilla/dom/ipc/IPCBlobInputStreamParent.h"
+    ),
+
+    ("PLoginReputation", "parent"): ("LoginReputationParent", "mozilla/LoginReputationIPC.h"),
+
+    ("PMedia", "child"): ("Child", "mozilla/media/MediaChild.h"),
+
+    ("PPendingIPCBlob", "child"): ("PendingIPCBlobChild", "mozilla/dom/ipc/PendingIPCBlobChild.h"),
+    ("PPendingIPCBlob", "parent"): (
+        "mozilla::dom::PendingIPCBlobParent", "mozilla/dom/ipc/PendingIPCBlobParent.h"
+    ),
+
+    ("PPresentationRequest", "child"): (
+        "PresentationRequestChild", "mozilla/dom/PresentationChild.h"
+    ),
+    ("PPresentationRequest", "parent"): (
+        "PresentationRequestParent", "mozilla/dom/PresentationParent.h"
+    ),
+
+    ("PPrinting", "child"): ("nsPrintingProxy", "nsPrintingProxy.h"),
+    ("PPrinting", "parent"): ("PrintingParent", "mozilla/embedding/printingui/PrintingParent.h"),
+
+    ("PPSMContentDownloader", "child"): (
+        "PSMContentDownloaderChild", "mozilla/psm/PSMContentListener.h"
+    ),
+    ("PPSMContentDownloader", "parent"): (
+        "PSMContentDownloaderParent", "mozilla/psm/PSMContentListener.h"
+    ),
+
+    ("PRemoteSpellcheckEngine", "child"): (
+        "RemoteSpellcheckEngineChild", "mozilla/RemoteSpellCheckEngineChild.h"
+    ),
+    ("PRemoteSpellcheckEngine", "parent"): (
+        "RemoteSpellcheckEngineParent", "mozilla/RemoteSpellCheckEngineParent.h"
+    ),
+
+    ("PScriptCache", "child"): ("ScriptCacheChild", "mozilla/loader/ScriptCacheActors.h"),
+    ("PScriptCache", "parent"): ("ScriptCacheParent", "mozilla/loader/ScriptCacheActors.h"),
+
+    ("PTCPServerSocket", "child"): (
+        "mozilla::dom::TCPServerSocketChild", "mozilla/dom/network/TCPServerSocketChild.h"
+    ),
+    ("PTCPServerSocket", "parent"): (
+        "mozilla::dom::TCPServerSocketParent", "mozilla/dom/network/TCPServerSocketParent.h"
+    ),
+    ("PTCPSocket", "child"): (
+        "mozilla::dom::TCPSocketChild", "mozilla/dom/network/TCPSocketChild.h"
+    ),
+    ("PTCPSocket", "parent"): (
+        "mozilla::dom::TCPSocketParent", "mozilla/dom/network/TCPSocketParent.h"
+    ),
+
+    ("PTemporaryIPCBlob", "child"): (
+        "mozilla::dom::TemporaryIPCBlobChild", "mozilla/dom/ipc/TemporaryIPCBlobChild.h"
+    ),
+    ("PTemporaryIPCBlob", "parent"): (
+        "mozilla::dom::TemporaryIPCBlobParent", "mozilla/dom/ipc/TemporaryIPCBlobParent.h"
+    ),
+
+    ("PTestShellCommand", "parent"): ("TestShellCommandParent", "mozilla/ipc/TestShellParent.h"),
+
+    ("PTransportProvider", "child"): (
+        "TransportProviderChild", "mozilla/net/IPCTransportProvider.h"
+    ),
+    ("PTransportProvider", "parent"): (
+        "TransportProviderParent", "mozilla/net/IPCTransportProvider.h"
+    ),
+
+    ("PUDPSocket", "child"): (
+        "mozilla::dom::UDPSocketChild", "mozilla/dom/network/UDPSocketChild.h"
+    ),
+    ("PUDPSocket", "parent"): (
+        "mozilla::dom::UDPSocketParent", "mozilla/dom/network/UDPSocketParent.h"
+    ),
+
+    ("PURLClassifierLocal", "child"): (
+        "URLClassifierLocalChild", "mozilla/dom/URLClassifierChild.h"
+    ),
+    ("PURLClassifierLocal", "parent"): (
+        "URLClassifierLocalParent", "mozilla/dom/URLClassifierParent.h"
+    ),
+
+    ("PVR", "child"): ("VRChild", "VRChild.h"),
+    ("PVR", "parent"): ("VRParent", "VRParent.h"),
+    ("PVRGPU", "child"): ("VRGPUChild", "VRGPUChild.h"),
+    ("PVRGPU", "parent"): ("VRGPUParent", "VRGPUParent.h"),
+    ("PVRLayer", "child"): ("VRLayerChild", "VRLayerChild.h"),
+    ("PVRManager", "child"): ("VRManagerChild", "VRManagerChild.h"),
+    ("PVRManager", "parent"): ("VRManagerParent", "VRManagerParent.h"),
+
+    ("PWebSocket", "child"): ("WebSocketChannelChild", "mozilla/net/WebSocketChannelChild.h"),
+    ("PWebSocket", "parent"): ("WebSocketChannelParent", "mozilla/net/WebSocketChannelParent.h"),
+}
+
+# Our long term goal is to burn this list down, so new entries should be added
+# extremely sparingly and only with a very good reason! You must have an IPC
+# peer's r+ to add something new!
+
+# set() of (Protocol, side)
+VIRTUAL_CALL_CLASSES = set([
+    # Defined as a strange template
+    ("PJavaScript", "child"),
+    ("PJavaScript", "parent"),
+    ("PMedia", "parent"),
+    ("PTexture", "parent"),
+
+    # Defined in a .cpp
+    ("PAsmJSCacheEntry", "child"),
+    ("PAsmJSCacheEntry", "parent"),
+    ("PBackgroundFileHandle", "parent"),
+    ("PBackgroundFileRequest", "parent"),
+    ("PBackgroundIDBCursor", "parent"),
+    ("PBackgroundIDBDatabase", "parent"),
+    ("PBackgroundIDBDatabaseFile", "child"),
+    ("PBackgroundIDBDatabaseFile", "parent"),
+    ("PBackgroundIDBDatabaseRequest", "parent"),
+    ("PBackgroundIDBFactory", "parent"),
+    ("PBackgroundIDBFactoryRequest", "parent"),
+    ("PBackgroundIDBRequest", "parent"),
+    ("PBackgroundIDBTransaction", "parent"),
+    ("PBackgroundIDBVersionChangeTransaction", "parent"),
+    ("PBackgroundIndexedDBUtils", "parent"),
+    ("PBackgroundLSDatabase", "parent"),
+    ("PBackgroundLSObserver", "parent"),
+    ("PBackgroundLSRequest", "parent"),
+    ("PBackgroundLSSimpleRequest", "parent"),
+    ("PBackgroundLSSnapshot", "parent"),
+    ("PBackgroundSDBConnection", "parent"),
+    ("PBackgroundSDBRequest", "parent"),
+    ("PBackgroundTest", "child"),
+    ("PBackgroundTest", "parent"),
+    ("PChildToParentStream", "child"),
+    ("PChildToParentStream", "parent"),
+    ("PContentPermissionRequest", "parent"),
+    ("PCycleCollectWithLogs", "child"),
+    ("PCycleCollectWithLogs", "parent"),
+    ("PHal", "child"),
+    ("PHal", "parent"),
+    ("PIndexedDBPermissionRequest", "parent"),
+    ("PParentToChildStream", "child"),
+    ("PParentToChildStream", "parent"),
+    ("PProcessHangMonitor", "child"),
+    ("PProcessHangMonitor", "parent"),
+    ("PQuota", "parent"),
+    ("PQuotaRequest", "parent"),
+    ("PQuotaUsageRequest", "parent"),
+    ("PSimpleChannel", "child"),
+    ("PTexture", "child"),
+
+    # .h is not exported
+    ("PBackground", "child"),
+    ("PBackground", "parent"),
+    ("PBackgroundFileHandle", "child"),
+    ("PBackgroundFileRequest", "child"),
+    ("PBackgroundIDBCursor", "child"),
+    ("PBackgroundIDBDatabase", "child"),
+    ("PBackgroundIDBDatabaseRequest", "child"),
+    ("PBackgroundIDBFactory", "child"),
+    ("PBackgroundIDBFactoryRequest", "child"),
+    ("PBackgroundIDBRequest", "child"),
+    ("PBackgroundIDBTransaction", "child"),
+    ("PBackgroundIDBVersionChangeTransaction", "child"),
+    ("PBackgroundIndexedDBUtils", "child"),
+    ("PBackgroundLSDatabase", "child"),
+    ("PBackgroundLSObserver", "child"),
+    ("PBackgroundLSRequest", "child"),
+    ("PBackgroundLSSimpleRequest", "child"),
+    ("PBackgroundLSSnapshot", "child"),
+    ("PBackgroundMutableFile", "child"),
+    ("PBackgroundSDBConnection", "child"),
+    ("PBackgroundSDBRequest", "child"),
+    ("PBroadcastChannel", "child"),
+    ("PBroadcastChannel", "parent"),
+    ("PChromiumCDM", "child"),
+    ("PClientHandle", "child"),
+    ("PClientHandle", "parent"),
+    ("PClientHandleOp", "child"),
+    ("PClientHandleOp", "parent"),
+    ("PClientManager", "child"),
+    ("PClientManager", "parent"),
+    ("PClientManagerOp", "child"),
+    ("PClientManagerOp", "parent"),
+    ("PClientNavigateOp", "child"),
+    ("PClientNavigateOp", "parent"),
+    ("PClientOpenWindowOp", "child"),
+    ("PClientOpenWindowOp", "parent"),
+    ("PClientSource", "child"),
+    ("PClientSource", "parent"),
+    ("PClientSourceOp", "child"),
+    ("PClientSourceOp", "parent"),
+    ("PColorPicker", "child"),
+    ("PColorPicker", "parent"),
+    ("PDataChannel", "child"),
+    ("PFileChannel", "child"),
+    ("PFilePicker", "child"),
+    ("PFunctionBroker", "child"),
+    ("PFunctionBroker", "parent"),
+    ("PHandlerService", "child"),
+    ("PHandlerService", "parent"),
+    ("PPluginBackgroundDestroyer", "child"),
+    ("PPluginBackgroundDestroyer", "parent"),
+    ("PPrintProgressDialog", "child"),
+    ("PPrintProgressDialog", "parent"),
+    ("PPrintSettingsDialog", "child"),
+    ("PPrintSettingsDialog", "parent"),
+    ("PQuota", "child"),
+    ("PQuotaRequest", "child"),
+    ("PQuotaUsageRequest", "child"),
+    ("PRemoteVideoDecoder", "child"),
+    ("PRemoteVideoDecoder", "parent"),
+    ("PServiceWorker", "child"),
+    ("PServiceWorker", "parent"),
+    ("PServiceWorkerContainer", "child"),
+    ("PServiceWorkerContainer", "parent"),
+    ("PServiceWorkerRegistration", "child"),
+    ("PServiceWorkerRegistration", "parent"),
+    ("PServiceWorkerUpdater", "child"),
+    ("PServiceWorkerUpdater", "parent"),
+    ("PVideoDecoder", "child"),
+    ("PVideoDecoder", "parent"),
+    ("PVRLayer", "parent"),
+    ("PWebBrowserPersistResources", "child"),
+    ("PWebBrowserPersistResources", "parent"),
+    ("PWebBrowserPersistSerialize", "child"),
+    ("PWebBrowserPersistSerialize", "parent"),
+    ("PWebrtcGlobal", "child"),
+    ("PWebrtcGlobal", "parent"),
+
+    # .h is only exported on some platforms/configs
+    ("PCameras", "child"),
+    ("PCameras", "parent"),
+    ("PCompositorWidget", "child"),
+    ("PCompositorWidget", "parent"),
+    ("PDocAccessible", "child"),
+    ("PDocAccessible", "parent"),
+    ("PPluginSurface", "parent"),
+    ("PPluginWidget", "child"),
+    ("PPluginWidget", "parent"),
+    ("PProfiler", "child"),
+    ("PProfiler", "parent"),
+    ("PSpeechSynthesisRequest", "child"),
+    ("PSpeechSynthesisRequest", "parent"),
+    ("PStunAddrsRequest", "child"),
+    ("PStunAddrsRequest", "parent"),
+    ("PWebrtcProxyChannel", "child"),
+    ("PWebrtcProxyChannel", "parent"),
+
+    # .h includes something that's a LOCAL_INCLUDE
+    ("PBackgroundLocalStorageCache", "child"),
+    ("PBackgroundLocalStorageCache", "parent"),
+    ("PBackgroundStorage", "child"),
+    ("PBackgroundStorage", "parent"),
+    ("PBrowserStream", "parent"),
+    ("PExternalHelperApp", "parent"),
+    ("PFTPChannel", "child"),
+    ("PFTPChannel", "parent"),
+    ("PHttpChannel", "child"),
+    ("PHttpChannel", "parent"),
+    ("PWyciwygChannel", "child"),
+
+    # bug 1513911
+    ("PIndexedDBPermissionRequest", "child"),
+
+    # Recv* methods are MOZ_CAN_RUN_SCRIPT and OnMessageReceived is not, so
+    # it's not allowed to call them.
+    ("PBrowser", "child"),
+
+    # can't be included safely for compilation error reasons
+    ("PGMPContent", "parent"),
+    ("PGMPService", "child"),
+    ("PGMPService", "parent"),
+    ("PGMPStorage", "parent"),
+    ("PGMPVideoDecoder", "parent"),
+    ("PGMPVideoEncoder", "parent"),
+    ("PWebRenderBridge", "parent"),
+
+    # Not actually subclassed
+    ("PLoginReputation", "child"),
+    ("PPluginSurface", "child"),
+    ("PTestShellCommand", "child"),
+])

--- a/ipc/ipdl/ipdl/lower.py
+++ b/ipc/ipdl/ipdl/lower.py
@@ -4,18 +4,20 @@
 
 import re
 from copy import deepcopy
 from collections import OrderedDict
 
 import ipdl.ast
 import ipdl.builtin
 from ipdl.cxx.ast import *
+from ipdl.direct_call import VIRTUAL_CALL_CLASSES, DIRECT_CALL_OVERRIDES
 from ipdl.type import ActorType, UnionType, TypeVisitor, builtinHeaderIncludes
 
+
 # -----------------------------------------------------------------------------
 # "Public" interface to lowering
 ##
 
 
 class LowerToCxx:
     def lower(self, tu, segmentcapacitydict):
         '''returns |[ header: File ], [ cpp : File ]| representing the
@@ -2946,16 +2948,28 @@ class _GenerateProtocolActorCode(ipdl.as
         actortype = ActorType(tu.protocol.decl.type)
         traitsdecl, traitsdefn = _ParamTraits.actorPickling(actortype, self.side)
 
         self.hdrfile.addthings(
             [traitsdecl, Whitespace.NL] + _includeGuardEnd(hf)
         )
 
         # make the .cpp file
+        if (self.protocol.name, self.side) not in VIRTUAL_CALL_CLASSES:
+            if (self.protocol.name, self.side) in DIRECT_CALL_OVERRIDES:
+                (_, header_file) = DIRECT_CALL_OVERRIDES[self.protocol.name, self.side]
+            else:
+                assert self.protocol.name.startswith("P")
+                header_file = "{}/{}{}.h".format(
+                    "/".join(n.name for n in self.protocol.namespaces),
+                    self.protocol.name[1:],
+                    self.side.capitalize(),
+                )
+            self.externalIncludes.add(header_file)
+
         cf.addthings([
             _DISCLAIMER,
             Whitespace.NL,
             CppDirective(
                 'include',
                 '"' + _protocolHeaderName(self.protocol, self.side) + '.h"')]
             + setToIncludes(self.externalIncludes))
 
@@ -3729,17 +3743,34 @@ class _GenerateProtocolActorCode(ipdl.as
     # -------------------------------------------------------------------------
     # The next few functions are the crux of the IPDL code generator.
     # They generate code for all the nasty work of message
     # serialization/deserialization and dispatching handlers for
     # received messages.
     ##
 
     def thisCall(self, function, args):
-        return ExprCall(ExprVar(function), args=args)
+        # If we're a direct call type, we cast `this` to the derived class
+        # before performing the call. Otherwise just emit the virtual call.
+        if (self.protocol.name, self.side) in VIRTUAL_CALL_CLASSES:
+            return ExprCall(ExprVar(function), args=args)
+
+        if (self.protocol.name, self.side) in DIRECT_CALL_OVERRIDES:
+            (class_name, _) = DIRECT_CALL_OVERRIDES[self.protocol.name, self.side]
+        else:
+            assert self.protocol.name.startswith("P")
+            class_name = "{}{}".format(self.protocol.name[1:], self.side.capitalize())
+        return ExprCall(
+            ExprSelect(
+                ExprCast(ExprVar("this"), Type(class_name, ptr=True), static=True),
+                "->",
+                ExprVar(function)
+            ),
+            args=args
+        )
 
     def visitMessageDecl(self, md):
         isctor = md.decl.type.isCtor()
         isdtor = md.decl.type.isDtor()
         decltype = md.decl.type
         sendmethod = None
         movesendmethod = None
         promisesendmethod = None

--- a/ipc/testshell/TestShellParent.h
+++ b/ipc/testshell/TestShellParent.h
@@ -17,28 +17,32 @@
 
 namespace mozilla {
 
 namespace ipc {
 
 class TestShellCommandParent;
 
 class TestShellParent : public PTestShellParent {
+  friend class PTestShellParent;
+
  public:
   virtual void ActorDestroy(ActorDestroyReason aWhy) override;
 
   PTestShellCommandParent* AllocPTestShellCommandParent(
       const nsString& aCommand) override;
 
   bool DeallocPTestShellCommandParent(PTestShellCommandParent* aActor) override;
 
   bool CommandDone(TestShellCommandParent* aActor, const nsString& aResponse);
 };
 
 class TestShellCommandParent : public PTestShellCommandParent {
+  friend class PTestShellCommandParent;
+
  public:
   TestShellCommandParent() {}
 
   bool SetCallback(JSContext* aCx, const JS::Value& aCallback);
 
   bool RunCallback(const nsString& aResponse);
 
   void ReleaseCallback();

--- a/js/xpconnect/loader/ScriptCacheActors.h
+++ b/js/xpconnect/loader/ScriptCacheActors.h
@@ -16,16 +16,18 @@ class FileDescriptor;
 }
 
 namespace loader {
 
 using mozilla::ipc::FileDescriptor;
 using mozilla::ipc::IPCResult;
 
 class ScriptCacheParent final : public PScriptCacheParent {
+  friend class PScriptCacheParent;
+
  public:
   explicit ScriptCacheParent(bool wantCacheData)
       : mWantCacheData(wantCacheData) {}
 
  protected:
   virtual IPCResult Recv__delete__(nsTArray<ScriptData>&& scripts) override;
 
   virtual void ActorDestroy(ActorDestroyReason aWhy) override;

--- a/layout/ipc/VsyncChild.h
+++ b/layout/ipc/VsyncChild.h
@@ -24,16 +24,17 @@ namespace layout {
 // The PVsyncChild actor receives a vsync event from the main process and
 // delivers it to the child process. Currently this is restricted to the main
 // thread only. The actor will stay alive until the process dies or its
 // PVsyncParent actor dies.
 class VsyncChild final : public PVsyncChild {
   NS_INLINE_DECL_REFCOUNTING(VsyncChild)
 
   friend class mozilla::ipc::BackgroundChildImpl;
+  friend class PVsyncChild;
 
  public:
   // Hide the SendObserve/SendUnobserve in PVsyncChild. We add an flag
   // mObservingVsync to handle the race problem of unobserving vsync event.
   bool SendObserve();
   bool SendUnobserve();
 
   // Bind a VsyncObserver into VsyncChild after ipc channel connected.

--- a/layout/ipc/VsyncParent.h
+++ b/layout/ipc/VsyncParent.h
@@ -22,16 +22,17 @@ class BackgroundParentImpl;
 
 namespace layout {
 
 // Use PBackground thread in the main process to send vsync notifications to
 // content process. This actor will be released when its parent protocol calls
 // DeallocPVsyncParent().
 class VsyncParent final : public PVsyncParent, public VsyncObserver {
   friend class mozilla::ipc::BackgroundParentImpl;
+  friend class PVsyncParent;
 
  private:
   static already_AddRefed<VsyncParent> Create();
 
   VsyncParent();
   virtual ~VsyncParent();
 
   virtual bool NotifyVsync(const VsyncEvent& aVsync) override;

--- a/media/mtransport/ipc/StunAddrsRequestChild.h
+++ b/media/mtransport/ipc/StunAddrsRequestChild.h
@@ -22,16 +22,18 @@ class StunAddrsListener {
  protected:
   virtual ~StunAddrsListener() {}
 
   ThreadSafeAutoRefCnt mRefCnt;
   NS_DECL_OWNINGTHREAD
 };
 
 class StunAddrsRequestChild final : public PStunAddrsRequestChild {
+  friend class PStunAddrsRequestChild;
+
  public:
   explicit StunAddrsRequestChild(StunAddrsListener* listener,
                                  nsIEventTarget* mainThreadEventTarget);
 
   NS_IMETHOD_(MozExternalRefCountType) AddRef();
   NS_IMETHOD_(MozExternalRefCountType) Release();
 
   // Not sure why AddIPDLReference & ReleaseIPDLReference don't come

--- a/media/mtransport/ipc/StunAddrsRequestParent.h
+++ b/media/mtransport/ipc/StunAddrsRequestParent.h
@@ -6,16 +6,18 @@
 #define mozilla_net_StunAddrsRequestParent_h
 
 #include "mozilla/net/PStunAddrsRequestParent.h"
 
 namespace mozilla {
 namespace net {
 
 class StunAddrsRequestParent : public PStunAddrsRequestParent {
+  friend class PStunAddrsRequestParent;
+
  public:
   StunAddrsRequestParent();
 
   NS_IMETHOD_(MozExternalRefCountType) AddRef();
   NS_IMETHOD_(MozExternalRefCountType) Release();
 
   mozilla::ipc::IPCResult Recv__delete__() override;
 

--- a/netwerk/cookie/CookieServiceChild.h
+++ b/netwerk/cookie/CookieServiceChild.h
@@ -26,16 +26,18 @@ namespace mozilla {
 namespace net {
 class CookieStruct;
 
 class CookieServiceChild : public PCookieServiceChild,
                            public nsICookieService,
                            public nsIObserver,
                            public nsITimerCallback,
                            public nsSupportsWeakReference {
+  friend class PCookieServiceChild;
+
  public:
   NS_DECL_ISUPPORTS
   NS_DECL_NSICOOKIESERVICE
   NS_DECL_NSIOBSERVER
   NS_DECL_NSITIMERCALLBACK
 
   typedef nsTArray<RefPtr<nsCookie>> CookiesList;
   typedef nsClassHashtable<nsCookieKey, CookiesList> CookiesMap;

--- a/netwerk/cookie/CookieServiceParent.h
+++ b/netwerk/cookie/CookieServiceParent.h
@@ -14,16 +14,18 @@ class nsCookieService;
 namespace mozilla {
 class OriginAttributes;
 }
 
 namespace mozilla {
 namespace net {
 
 class CookieServiceParent : public PCookieServiceParent {
+  friend class PCookieServiceParent;
+
  public:
   CookieServiceParent();
   virtual ~CookieServiceParent() = default;
 
   void TrackCookieLoad(nsIChannel *aChannel);
 
   void RemoveBatchDeletedCookies(nsIArray *aCookieList);
 

--- a/netwerk/dns/DNSRequestChild.h
+++ b/netwerk/dns/DNSRequestChild.h
@@ -13,16 +13,18 @@
 #include "nsIDNSListener.h"
 #include "nsIDNSByTypeRecord.h"
 #include "nsIEventTarget.h"
 
 namespace mozilla {
 namespace net {
 
 class DNSRequestChild final : public PDNSRequestChild, public nsICancelable {
+  friend class PDNSRequestChild;
+
  public:
   NS_DECL_THREADSAFE_ISUPPORTS
   NS_DECL_NSICANCELABLE
 
   DNSRequestChild(const nsACString& aHost, const uint16_t& aType,
                   const OriginAttributes& aOriginAttributes,
                   const uint32_t& aFlags, nsIDNSListener* aListener,
                   nsIEventTarget* target);

--- a/netwerk/ipc/NeckoChild.h
+++ b/netwerk/ipc/NeckoChild.h
@@ -11,16 +11,18 @@
 #include "mozilla/net/PNeckoChild.h"
 #include "mozilla/net/NeckoCommon.h"
 
 namespace mozilla {
 namespace net {
 
 // Header file contents
 class NeckoChild : public PNeckoChild {
+  friend class PNeckoChild;
+
  public:
   NeckoChild() = default;
   virtual ~NeckoChild();
 
   static void InitNeckoChild();
 
  protected:
   virtual PHttpChannelChild* AllocPHttpChannelChild(

--- a/netwerk/ipc/NeckoParent.h
+++ b/netwerk/ipc/NeckoParent.h
@@ -22,16 +22,18 @@ namespace net {
 enum PBOverrideStatus {
   kPBOverride_Unset = 0,
   kPBOverride_Private,
   kPBOverride_NotPrivate
 };
 
 // Header file contents
 class NeckoParent : public PNeckoParent {
+  friend class PNeckoParent;
+
  public:
   NeckoParent();
   virtual ~NeckoParent() = default;
 
   MOZ_MUST_USE
   static const char* GetValidatedOriginAttributes(
       const SerializedLoadContext& aSerialized, PContentParent* aBrowser,
       nsIPrincipal* aRequestingPrincipal, mozilla::OriginAttributes& aAttrs);

--- a/netwerk/protocol/http/HttpBackgroundChannelChild.h
+++ b/netwerk/protocol/http/HttpBackgroundChannelChild.h
@@ -17,16 +17,17 @@ using mozilla::ipc::IPCResult;
 
 namespace mozilla {
 namespace net {
 
 class HttpChannelChild;
 
 class HttpBackgroundChannelChild final : public PHttpBackgroundChannelChild {
   friend class BackgroundChannelCreateCallback;
+  friend class PHttpBackgroundChannelChild;
 
  public:
   explicit HttpBackgroundChannelChild();
 
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(HttpBackgroundChannelChild)
 
   // Associate this background channel with a HttpChannelChild and
   // initiate the createion of the PBackground IPC channel.

--- a/netwerk/protocol/http/TrackingDummyChannelChild.h
+++ b/netwerk/protocol/http/TrackingDummyChannelChild.h
@@ -14,16 +14,18 @@
 
 class nsIHttpChannel;
 class nsIURI;
 
 namespace mozilla {
 namespace net {
 
 class TrackingDummyChannelChild final : public PTrackingDummyChannelChild {
+  friend class PTrackingDummyChannelChild;
+
  public:
   static bool Create(nsIHttpChannel* aChannel, nsIURI* aURI,
                      const std::function<void(bool)>& aCallback);
 
   // Used by PNeckoChild only!
   TrackingDummyChannelChild();
   ~TrackingDummyChannelChild();
 

--- a/netwerk/protocol/websocket/WebSocketChannelChild.h
+++ b/netwerk/protocol/websocket/WebSocketChannelChild.h
@@ -17,16 +17,18 @@ namespace mozilla {
 namespace net {
 
 class ChannelEvent;
 class ChannelEventQueue;
 
 class WebSocketChannelChild final : public BaseWebSocketChannel,
                                     public PWebSocketChild,
                                     public NeckoTargetHolder {
+  friend class PWebSocketChild;
+
  public:
   explicit WebSocketChannelChild(bool aSecure);
 
   NS_DECL_THREADSAFE_ISUPPORTS
 
   // nsIWebSocketChannel methods BaseWebSocketChannel didn't implement for us
   //
   NS_IMETHOD AsyncOpen(nsIURI* aURI, const nsACString& aOrigin,

--- a/netwerk/protocol/websocket/WebSocketChannelParent.h
+++ b/netwerk/protocol/websocket/WebSocketChannelParent.h
@@ -19,16 +19,18 @@
 class nsIAuthPromptProvider;
 
 namespace mozilla {
 namespace net {
 
 class WebSocketChannelParent : public PWebSocketParent,
                                public nsIWebSocketListener,
                                public nsIInterfaceRequestor {
+  friend class PWebSocketParent;
+
   ~WebSocketChannelParent() = default;
 
  public:
   NS_DECL_THREADSAFE_ISUPPORTS
   NS_DECL_NSIWEBSOCKETLISTENER
   NS_DECL_NSIINTERFACEREQUESTOR
 
   WebSocketChannelParent(nsIAuthPromptProvider* aAuthProvider,

--- a/netwerk/protocol/websocket/WebSocketEventListenerParent.h
+++ b/netwerk/protocol/websocket/WebSocketEventListenerParent.h
@@ -12,16 +12,18 @@
 
 namespace mozilla {
 namespace net {
 
 class WebSocketEventService;
 
 class WebSocketEventListenerParent final : public PWebSocketEventListenerParent,
                                            public nsIWebSocketEventListener {
+  friend class PWebSocketEventListenerParent;
+
  public:
   NS_DECL_ISUPPORTS
   NS_DECL_NSIWEBSOCKETEVENTLISTENER
 
   explicit WebSocketEventListenerParent(uint64_t aInnerWindowID);
 
  private:
   ~WebSocketEventListenerParent();

--- a/netwerk/protocol/wyciwyg/WyciwygChannelParent.h
+++ b/netwerk/protocol/wyciwyg/WyciwygChannelParent.h
@@ -18,16 +18,18 @@ namespace dom {
 class PBrowserParent;
 }  // namespace dom
 
 namespace net {
 
 class WyciwygChannelParent : public PWyciwygChannelParent,
                              public nsIStreamListener,
                              public nsIInterfaceRequestor {
+  friend class PWyciwygChannelParent;
+
  public:
   NS_DECL_ISUPPORTS
   NS_DECL_NSIREQUESTOBSERVER
   NS_DECL_NSISTREAMLISTENER
   NS_DECL_NSIINTERFACEREQUESTOR
 
   WyciwygChannelParent();
 

--- a/toolkit/components/extensions/webrequest/StreamFilterChild.h
+++ b/toolkit/components/extensions/webrequest/StreamFilterChild.h
@@ -22,16 +22,17 @@ namespace extensions {
 using mozilla::dom::StreamFilterStatus;
 using mozilla::ipc::IPCResult;
 
 class StreamFilter;
 
 class StreamFilterChild final : public PStreamFilterChild,
                                 public StreamFilterBase {
   friend class StreamFilter;
+  friend class PStreamFilterChild;
 
  public:
   NS_INLINE_DECL_REFCOUNTING(StreamFilterChild)
 
   StreamFilterChild() : mState(State::Uninitialized), mReceivedOnStop(false) {}
 
   enum class State {
     // Uninitialized, waiting for constructor response from parent.

--- a/toolkit/components/extensions/webrequest/StreamFilterParent.h
+++ b/toolkit/components/extensions/webrequest/StreamFilterParent.h
@@ -39,16 +39,18 @@ namespace extensions {
 using namespace mozilla::dom;
 using mozilla::ipc::IPCResult;
 
 class StreamFilterParent final : public PStreamFilterParent,
                                  public nsIStreamListener,
                                  public nsIThreadRetargetableStreamListener,
                                  public nsIRequest,
                                  public StreamFilterBase {
+  friend class PStreamFilterParent;
+
  public:
   NS_DECL_THREADSAFE_ISUPPORTS
   NS_DECL_NSISTREAMLISTENER
   NS_DECL_NSIREQUEST
   NS_DECL_NSIREQUESTOBSERVER
   NS_DECL_NSITHREADRETARGETABLESTREAMLISTENER
 
   StreamFilterParent();

--- a/toolkit/components/printingui/ipc/nsPrintingProxy.h
+++ b/toolkit/components/printingui/ipc/nsPrintingProxy.h
@@ -12,16 +12,18 @@
 namespace mozilla {
 namespace layout {
 class PRemotePrintJobChild;
 }
 }  // namespace mozilla
 
 class nsPrintingProxy final : public nsIPrintingPromptService,
                               public mozilla::embedding::PPrintingChild {
+  friend class mozilla::embedding::PPrintingChild;
+
  public:
   static already_AddRefed<nsPrintingProxy> GetInstance();
 
   NS_DECL_ISUPPORTS
   NS_DECL_NSIPRINTINGPROMPTSERVICE
 
   /**
    * Used to proxy nsIPrintSettings.savePrintSettingsToPrefs calls to the