Allow media track switching.

media/renderers/renderer_impl.cc

Index: media/renderers/renderer_impl.cc
diff --git a/media/renderers/renderer_impl.cc b/media/renderers/renderer_impl.cc
index f03b2da865c7f2b02b748b4f9f7f26f2627ebd50..f701ba7806386b036721944396a203951df491de 100644
--- a/media/renderers/renderer_impl.cc
+++ b/media/renderers/renderer_impl.cc
@@ -80,6 +80,8 @@ RendererImpl::RendererImpl(
       task_runner_(task_runner),
       audio_renderer_(std::move(audio_renderer)),
       video_renderer_(std::move(video_renderer)),
+      current_audio_stream_(nullptr),
+      current_video_stream_(nullptr),
       time_source_(NULL),
       time_ticking_(false),
       playback_rate_(0.0),
@@ -236,8 +238,8 @@ void RendererImpl::OnStreamStatusChanged(DemuxerStream* stream,
   if (stream->type() == DemuxerStream::VIDEO) {
     DCHECK(video_renderer_);
     restarting_video_ = true;
-    video_renderer_->Flush(
-        base::Bind(&RendererImpl::RestartVideoRenderer, weak_this_, time));
+    video_renderer_->Flush(base::Bind(&RendererImpl::RestartVideoRenderer,
+                                      weak_this_, stream, time));
   } else if (stream->type() == DemuxerStream::AUDIO) {
     DCHECK(audio_renderer_);
     DCHECK(time_source_);
@@ -249,30 +251,76 @@ void RendererImpl::OnStreamStatusChanged(DemuxerStream* stream,
       time_ticking_ = false;
       time_source_->StopTicking();
     }
-    audio_renderer_->Flush(
-        base::Bind(&RendererImpl::RestartAudioRenderer, weak_this_, time));
+    audio_renderer_->Flush(base::Bind(&RendererImpl::RestartAudioRenderer,
+                                      weak_this_, stream, time));
   }
 }
 
-void RendererImpl::RestartVideoRenderer(base::TimeDelta time) {
-  DVLOG(3) << __func__;
+void RendererImpl::RestartVideoRenderer(DemuxerStream* stream,
+                                        base::TimeDelta time) {
+  DVLOG(3) << __func__ << " stream=" << stream << " time=" << time.InSecondsF();
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(video_renderer_);
   DCHECK_EQ(state_, STATE_PLAYING);
+  if (stream != current_video_stream_) {
+    DVLOG(3) << __func__ << ": detected stream change, reinitializing decoder";
+    current_video_stream_ = stream;
+    video_renderer_->OnTimeStopped();
+    video_renderer_->Initialize(
+        stream, cdm_context_, video_renderer_client_.get(),
+        base::Bind(&RendererImpl::GetWallClockTimes, base::Unretained(this)),
+        base::Bind(&RendererImpl::OnVideoRendererReinitCompleted, weak_this_,
+                   stream, time));
+    return;
+  }
   video_ended_ = false;
   video_renderer_->StartPlayingFrom(time);
 }
 
-void RendererImpl::RestartAudioRenderer(base::TimeDelta time) {
-  DVLOG(3) << __func__;
+void RendererImpl::OnVideoRendererReinitCompleted(DemuxerStream* stream,
+                                                  base::TimeDelta time,
+                                                  PipelineStatus status) {
+  DVLOG(3) << __func__ << ": status=" << status;
+  if (status != PIPELINE_OK) {
+    OnError(status);
+    return;
+  }
+  DCHECK_EQ(stream, current_video_stream_);
+  RestartVideoRenderer(stream, time);
+}
+
+void RendererImpl::RestartAudioRenderer(DemuxerStream* stream,
+                                        base::TimeDelta time) {
+  DVLOG(3) << __func__ << " stream=" << stream << " time=" << time.InSecondsF();
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK_EQ(state_, STATE_PLAYING);
   DCHECK(time_source_);
   DCHECK(audio_renderer_);
+  if (stream != current_audio_stream_) {
+    DVLOG(3) << __func__ << ": detected stream change, reinitializing decoder";
+    current_audio_stream_ = stream;
+    audio_renderer_->Initialize(
+        stream, cdm_context_, audio_renderer_client_.get(),
+        base::Bind(&RendererImpl::OnAudioRendererReinitCompleted, weak_this_,
+                   stream, time));
+    return;
+  }
   audio_ended_ = false;
   audio_renderer_->StartPlaying();
 }
 
+void RendererImpl::OnAudioRendererReinitCompleted(DemuxerStream* stream,
+                                                  base::TimeDelta time,
+                                                  PipelineStatus status) {
+  DVLOG(3) << __func__ << ": status=" << status;
+  if (status != PIPELINE_OK) {
+    OnError(status);
+    return;
+  }
+  DCHECK_EQ(stream, current_audio_stream_);
+  RestartAudioRenderer(stream, time);
+}
+
 void RendererImpl::SetPlaybackRate(double playback_rate) {
   DVLOG(1) << __func__ << "(" << playback_rate << ")";
   DCHECK(task_runner_->BelongsToCurrentThread());
@@ -394,6 +442,8 @@ void RendererImpl::InitializeAudioRenderer() {
     return;
   }
 
+  current_audio_stream_ = audio_stream;
+
   audio_renderer_client_.reset(
       new RendererClientInternal(DemuxerStream::AUDIO, this));
   // Note: After the initialization of a renderer, error events from it may
@@ -442,6 +492,8 @@ void RendererImpl::InitializeVideoRenderer() {
     return;
   }
 
+  current_video_stream_ = video_stream;
+
   video_renderer_client_.reset(
       new RendererClientInternal(DemuxerStream::VIDEO, this));
   video_renderer_->Initialize(