Bug 1580659 - part4 : pulling the intial update after starting AudioChannelAgent. r=chunmin

Instead of calling those callback functions seperately, we could provide a function to pull those changes at once after starting the agent.

In addition, `WindowXXXChanged` are callback functions of `nsIAudioChannelAgentCallback`, so they should only be called by `AudioChannelAgent`, to indicate receiving the change from `AudioChannelService`. We should not call them directly.

Differential Revision: https://phabricator.services.mozilla.com/D45751

--HG--
extra : moz-landing-system : lando

dom/audiochannel/AudioChannelAgent.cpp

@@ -126,6 +126,17 @@ nsresult AudioChannelAgent::InitInternal(
   return NS_OK;
 }
 
+void AudioChannelAgent::PullInitialUpdate() {
+  RefPtr<AudioChannelService> service = AudioChannelService::Get();
+  MOZ_ASSERT(service);
+  MOZ_ASSERT(mIsRegToService);
+
+  AudioPlaybackConfig config = service->GetMediaConfig(mWindow);
+  WindowVolumeChanged();
+  WindowSuspendChanged(config.mSuspend);
+  WindowAudioCaptureChanged(InnerWindowID(), config.mCapturedAudio);
+}
+
 NS_IMETHODIMP
 AudioChannelAgent::NotifyStartedPlaying(AudioPlaybackConfig* aConfig,
                                         uint8_t aAudible) {

dom/audiochannel/AudioChannelAgent.h

@@ -30,6 +30,13 @@ class AudioChannelAgent : public nsIAudioChannelAgent {
 
   AudioChannelAgent();
 
+  // nsIAudioChannelAgentCallback MUST call this function after calling
+  // NotifyStartedPlaying() to require the initial update for
+  // volume/suspend/audio-capturing which might set before starting the agent.
+  // Ex. starting the agent in a tab which has been muted before, so the agent
+  // should apply mute state to its callback.
+  void PullInitialUpdate();
+
   void WindowVolumeChanged();
   void WindowSuspendChanged(nsSuspendedTypes aSuspend);
   void WindowAudioCaptureChanged(uint64_t aInnerWindowID, bool aCapture);

dom/html/HTMLMediaElement.cpp

@@ -1196,9 +1196,7 @@ class HTMLMediaElement::AudioChannelAgentCallback final
     }
 
     NotifyMediaStarted(mAudioChannelAgent->WindowID());
-    WindowVolumeChanged(config.mVolume, config.mMuted);
-    WindowSuspendChanged(config.mSuspend);
-    WindowAudioCaptureChanged(config.mCapturedAudio);
+    mAudioChannelAgent->PullInitialUpdate();
   }
 
   void StopAudioChanelAgent() {

dom/media/webaudio/AudioDestinationNode.cpp

@@ -628,9 +628,7 @@ void AudioDestinationNode::NotifyAudibleStateChanged(bool aAudible) {
     return;
   }
 
-  WindowVolumeChanged(config.mVolume, config.mMuted);
-  WindowSuspendChanged(config.mSuspend);
-  WindowAudioCaptureChanged(config.mCapturedAudio);
+  mAudioChannelAgent->PullInitialUpdate();
 }
 
 }  // namespace dom

dom/media/webspeech/synth/nsSpeechTask.cpp

@@ -346,8 +346,7 @@ void nsSpeechTask::CreateAudioChannelAgent() {
     return;
   }
 
-  WindowVolumeChanged(config.mVolume, config.mMuted);
-  WindowSuspendChanged(config.mSuspend);
+  mAudioChannelAgent->PullInitialUpdate();
 }
 
 void nsSpeechTask::DestroyAudioChannelAgent() {

dom/plugins/base/nsNPAPIPluginInstance.cpp

@@ -1114,15 +1114,7 @@ void nsNPAPIPluginInstance::NotifyStartedPlaying() {
     return;
   }
 
-  rv = WindowVolumeChanged(config.mVolume, config.mMuted);
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    return;
-  }
-
-  rv = WindowSuspendChanged(config.mSuspend);
-  if (NS_WARN_IF(NS_FAILED(rv))) {
-    return;
-  }
+  mAudioChannelAgent->PullInitialUpdate();
 }
 
 void nsNPAPIPluginInstance::NotifyStoppedPlaying() {