Bug 1672087 - P2. Recreate remote decoder when parent dies. r=mattwoodrow,bryce

The RDD process startup being asynchronous make the operation trivial. Unlike with the GPU process, we can immediately tell the MediaFormatDecoder that a new decoder is needed when the RDD died.

Recovery will immediately occur with little visible interruption.

Differential Revision: https://phabricator.services.mozilla.com/D98571

dom/media/ipc/RemoteAudioDecoder.cpp

@@ -13,7 +13,8 @@
 
 namespace mozilla {
 
-RemoteAudioDecoderChild::RemoteAudioDecoderChild() : RemoteDecoderChild() {}
+RemoteAudioDecoderChild::RemoteAudioDecoderChild()
+    : RemoteDecoderChild(RemoteDecodeIn::RddProcess) {}
 
 MediaResult RemoteAudioDecoderChild::ProcessOutput(
     DecodedOutputIPDL&& aDecodedData) {
@@ -38,7 +39,7 @@ MediaResult RemoteAudioDecoderChild::InitIPDL(
     const AudioInfo& aAudioInfo,
     const CreateDecoderParams::OptionSet& aOptions) {
   RefPtr<RemoteDecoderManagerChild> manager =
-      RemoteDecoderManagerChild::GetSingleton(RemoteDecodeIn::RddProcess);
+      RemoteDecoderManagerChild::GetSingleton(mLocation);
 
   // The manager isn't available because RemoteDecoderManagerChild has been
   // initialized with null end points and we don't want to decode video on RDD

dom/media/ipc/RemoteDecoderChild.cpp

@@ -9,10 +9,10 @@
 
 namespace mozilla {
 
-RemoteDecoderChild::RemoteDecoderChild(bool aRecreatedOnCrash)
+RemoteDecoderChild::RemoteDecoderChild(RemoteDecodeIn aLocation)
     : ShmemRecycleAllocator(this),
-      mThread(GetCurrentSerialEventTarget()),
-      mRecreatedOnCrash(aRecreatedOnCrash) {
+      mLocation(aLocation),
+      mThread(GetCurrentSerialEventTarget()) {
   MOZ_DIAGNOSTIC_ASSERT(
       RemoteDecoderManagerChild::GetManagerThread() &&
           RemoteDecoderManagerChild::GetManagerThread()->IsOnCurrentThread(),
@@ -30,9 +30,12 @@ void RemoteDecoderChild::HandleRejectionError(
   // longer be used.
 
   // The GPU/RDD process crashed.
-  if (mRecreatedOnCrash) {
-    // Defer reporting an error until we've recreated the manager so that
-    // it'll be safe for MediaFormatReader to recreate decoders
+  if (mLocation == RemoteDecodeIn::GpuProcess) {
+    // The GPU process will get automatically restarted by the parent process.
+    // Once it has been restarted the ContentChild will receive the message and
+    // will call GetManager()->InitForGPUProcess.
+    // We defer reporting an error until we've recreated the RemoteDecoder
+    // manager so that it'll be safe for MediaFormatReader to recreate decoders
     RefPtr<RemoteDecoderChild> self = this;
     GetManager()->RunWhenGPUProcessRecreated(NS_NewRunnableFunction(
         "RemoteDecoderChild::HandleRejectionError",
@@ -42,7 +45,10 @@ void RemoteDecoderChild::HandleRejectionError(
         }));
     return;
   }
-  aCallback(MediaResult(NS_ERROR_DOM_MEDIA_FATAL_ERR, __func__));
+  // The RDD process is restarted on demand and asynchronously, we can
+  // immediately inform the caller that a new decoder is needed. The RDD will
+  // then be restarted during the new decoder creation.
+  aCallback(MediaResult(NS_ERROR_DOM_MEDIA_NEED_NEW_DECODER, __func__));
 }
 
 // ActorDestroy is called if the channel goes down while waiting for a response.

dom/media/ipc/RemoteDecoderChild.h

@@ -24,7 +24,7 @@ class RemoteDecoderChild : public ShmemRecycleAllocator<RemoteDecoderChild>,
  public:
   NS_INLINE_DECL_THREADSAFE_REFCOUNTING(RemoteDecoderChild);
 
-  explicit RemoteDecoderChild(bool aRecreatedOnCrash = false);
+  explicit RemoteDecoderChild(RemoteDecodeIn aLocation);
 
   void ActorDestroy(ActorDestroyReason aWhy) override;
 
@@ -56,6 +56,7 @@ class RemoteDecoderChild : public ShmemRecycleAllocator<RemoteDecoderChild>,
 
   RefPtr<RemoteDecoderChild> mIPDLSelfRef;
   MediaDataDecoder::DecodedData mDecodedData;
+  const RemoteDecodeIn mLocation;
 
  private:
   const nsCOMPtr<nsISerialEventTarget> mThread;
@@ -74,7 +75,6 @@ class RemoteDecoderChild : public ShmemRecycleAllocator<RemoteDecoderChild>,
   nsCString mHardwareAcceleratedReason;
   nsCString mDescription;
   bool mIsHardwareAccelerated = false;
-  const bool mRecreatedOnCrash;
   MediaDataDecoder::ConversionRequired mConversion =
       MediaDataDecoder::ConversionRequired::kNeedNone;
 };

dom/media/ipc/RemoteVideoDecoder.cpp

@@ -55,9 +55,7 @@ KnowsCompositorVideo::TryCreateForIdentifier(
 }
 
 RemoteVideoDecoderChild::RemoteVideoDecoderChild(RemoteDecodeIn aLocation)
-    : RemoteDecoderChild(aLocation == RemoteDecodeIn::GpuProcess),
-      mBufferRecycleBin(new BufferRecycleBin),
-      mLocation(aLocation) {}
+    : RemoteDecoderChild(aLocation), mBufferRecycleBin(new BufferRecycleBin) {}
 
 MediaResult RemoteVideoDecoderChild::ProcessOutput(
     DecodedOutputIPDL&& aDecodedData) {

dom/media/ipc/RemoteVideoDecoder.h

@@ -47,9 +47,6 @@ class RemoteVideoDecoderChild : public RemoteDecoderChild {
 
  private:
   RefPtr<mozilla::layers::BufferRecycleBin> mBufferRecycleBin;
-
-  // The location of the RemoteVideoDecoderParent - Gpu or Rdd process.
-  const RemoteDecodeIn mLocation;
 };
 
 class RemoteVideoDecoderParent final : public RemoteDecoderParent {