Move VideoDecoder out of media pipeline.

media/filters/video_renderer_base.cc

Index: media/filters/video_renderer_base.cc
diff --git a/media/filters/video_renderer_base.cc b/media/filters/video_renderer_base.cc
index ffd942bbea602eca34e172b867853eea58c7278a..2be9a0785fd584b69220329935d7d1cd93a8736b 100644
--- a/media/filters/video_renderer_base.cc
+++ b/media/filters/video_renderer_base.cc
@@ -59,6 +59,11 @@ void VideoRendererBase::Flush(const base::Closure& callback) {
 }
 
 void VideoRendererBase::Stop(const base::Closure& callback) {
+  if (state_ == kStopped) {
+    callback.Run();
+    return;
+  }
+
   base::PlatformThreadHandle thread_to_join = base::kNullThreadHandle;
   {
     base::AutoLock auto_lock(lock_);
@@ -81,7 +86,7 @@ void VideoRendererBase::Stop(const base::Closure& callback) {
   if (thread_to_join != base::kNullThreadHandle)
     base::PlatformThread::Join(thread_to_join);
 
-  callback.Run();
+  decoder_->Stop(callback);
 }
 
 void VideoRendererBase::SetPlaybackRate(float playback_rate) {
@@ -101,7 +106,7 @@ void VideoRendererBase::Seek(base::TimeDelta time, const FilterStatusCB& cb) {
   AttemptRead_Locked();
 }
 
-void VideoRendererBase::Initialize(VideoDecoder* decoder,
+void VideoRendererBase::Initialize(const scoped_refptr<VideoDecoder>& decoder,
                                    const PipelineStatusCB& pipeline_status_cb,
                                    const StatisticsCB& statistics_cb,
                                    const VideoTimeCB& video_time_cb) {
@@ -452,7 +457,8 @@ void VideoRendererBase::AttemptFlush_Locked() {
   if (!pending_paint_ && !pending_read_) {
     state_ = kFlushed;
     current_frame_ = NULL;
-    ResetAndRunCB(&flush_callback_);
+    decoder_->Flush(flush_callback_);

[Ami GONE FROM CHROMIUM, 2012/03/14 20:05:01]

This change is unsafe if flushing the decoder causes the renderer to get flushed
again (the basic reason why ResetAndRunCB() isn't RunAndResetCB()).
The right way to do this is 
base::Closure flush_cb = flush_callback_;
flush_callback_.Reset();
decoder_->Flush(flush_cb);

[xhwang, 2012/03/14 22:28:41]

Done.

+    flush_callback_.Reset();
   }
 }