Bug 1309516 part 3 - make MediaDecoderReaderWrapper keeps the start time returned from reader;r=jwwang

MozReview-Commit-ID: F57avqCENTj

--HG--
extra : rebase_source : 4e61cb46687539f5b5b2a775b46ad5347ccc6e2a
extra : intermediate-source : 50c6ae37fa51c52d533bb5cdcd1267a869d49410
extra : source : cb9924bcc2c1d2a820b7b942c89feb861be85569

dom/media/MediaDecoderReaderWrapper.cpp

@@ -153,7 +153,7 @@ MediaDecoderReaderWrapper::StartTime() const
 {
   MOZ_ASSERT(mOwnerThread->IsCurrentThreadIn());
   MOZ_ASSERT(!mShutdown);
-  return media::TimeUnit::FromMicroseconds(mStartTimeRendezvous->StartTime());
+  return mStartTime.ref();
 }
 
 RefPtr<MediaDecoderReaderWrapper::MetadataPromise>
@@ -186,13 +186,6 @@ MediaDecoderReaderWrapper::RequestAudioData()
   auto p = InvokeAsync(mReader->OwnerThread(), mReader.get(), __func__,
                        &MediaDecoderReader::RequestAudioData);
 
-  if (!mStartTimeRendezvous->HaveStartTime()) {
-    p = p->Then(mOwnerThread, __func__, mStartTimeRendezvous.get(),
-                &StartTimeRendezvous::ProcessFirstSample<MediaData::AUDIO_DATA>,
-                &StartTimeRendezvous::FirstSampleRejected<MediaData::AUDIO_DATA>)
-         ->CompletionPromise();
-  }
-
   RefPtr<MediaDecoderReaderWrapper> self = this;
   mAudioDataRequest.Begin(p->Then(mOwnerThread, __func__,
     [self] (MediaData* aAudioSample) {
@@ -217,8 +210,7 @@ MediaDecoderReaderWrapper::RequestVideoData(bool aSkipToNextKeyframe,
   // a TimeStamp as its second parameter.
   TimeStamp videoDecodeStartTime = TimeStamp::Now();
 
-  if (aTimeThreshold.ToMicroseconds() > 0 &&
-      mStartTimeRendezvous->HaveStartTime()) {
+  if (aTimeThreshold.ToMicroseconds() > 0) {
     aTimeThreshold += StartTime();
   }
 
@@ -226,13 +218,6 @@ MediaDecoderReaderWrapper::RequestVideoData(bool aSkipToNextKeyframe,
                        &MediaDecoderReader::RequestVideoData,
                        aSkipToNextKeyframe, aTimeThreshold.ToMicroseconds());
 
-  if (!mStartTimeRendezvous->HaveStartTime()) {
-    p = p->Then(mOwnerThread, __func__, mStartTimeRendezvous.get(),
-                &StartTimeRendezvous::ProcessFirstSample<MediaData::VIDEO_DATA>,
-                &StartTimeRendezvous::FirstSampleRejected<MediaData::VIDEO_DATA>)
-         ->CompletionPromise();
-  }
-
   RefPtr<MediaDecoderReaderWrapper> self = this;
   mVideoDataRequest.Begin(p->Then(mOwnerThread, __func__,
     [self, videoDecodeStartTime] (MediaData* aVideoSample) {
@@ -389,23 +374,13 @@ MediaDecoderReaderWrapper::OnMetadataRead(MetadataHolder* aMetadata)
   if (mShutdown) {
     return;
   }
-  // Set up the start time rendezvous if it doesn't already exist (which is
-  // generally the case, unless we're coming out of dormant mode).
-  if (!mStartTimeRendezvous) {
-    mStartTimeRendezvous = new StartTimeRendezvous(
-      mOwnerThread, aMetadata->mInfo.HasAudio(),
-      aMetadata->mInfo.HasVideo(), mForceZeroStartTime);
 
-    RefPtr<MediaDecoderReaderWrapper> self = this;
-    mStartTimeRendezvous->AwaitStartTime()->Then(
-      mOwnerThread, __func__,
-      [self] ()  {
-        NS_ENSURE_TRUE_VOID(!self->mShutdown);
-        self->mReader->DispatchSetStartTime(self->StartTime().ToMicroseconds());
-      },
-      [] () {
-        NS_WARNING("Setting start time on reader failed");
-      });
+  if (mStartTime.isNothing()) {
+    mStartTime.emplace(aMetadata->mInfo.mStartTime);
+    // Note: MFR should be able to setup its start time by itself without going
+    // through here. MediaDecoderReader::DispatchSetStartTime() will be removed
+    // once we remove all the legacy readers' code in the following bugs.
+    mReader->DispatchSetStartTime(StartTime().ToMicroseconds());
   }
 }
 

dom/media/MediaDecoderReaderWrapper.h

@@ -131,6 +131,7 @@ private:
 
   bool mShutdown = false;
   RefPtr<StartTimeRendezvous> mStartTimeRendezvous;
+  Maybe<media::TimeUnit> mStartTime;
 
   MozPromiseRequestHolder<MediaDataPromise> mAudioDataRequest;
   MozPromiseRequestHolder<MediaDataPromise> mVideoDataRequest;