Add Stop() to AudioDecoder.

media/filters/audio_renderer_impl.cc

Index: media/filters/audio_renderer_impl.cc
diff --git a/media/filters/audio_renderer_impl.cc b/media/filters/audio_renderer_impl.cc
index f9b314d2ec2536ff43b18fd15ae2db222f61a4a0..09d6fef14d6167bbf1f065470ca65b6d7ece44b1 100644
--- a/media/filters/audio_renderer_impl.cc
+++ b/media/filters/audio_renderer_impl.cc
@@ -162,26 +162,48 @@ void AudioRendererImpl::ResetDecoder() {
 }
 
 void AudioRendererImpl::ResetDecoderDone() {
-  base::AutoLock auto_lock(lock_);
   if (state_ == kStopped)

[DaleCurtis, 2014/01/09 01:24:49]

State must be checked under lock; it can be changed on the audio thread. See the
comment on |lock_| for which variables must only be accessed under lock.

Just the callback should be run outside of lock.  Also it'd be helpful if this
method had a DCHECK(task_runnner_->BelongsToCurrentThread());  Ditto for
StopDecoderDone().

     return;
 
   DCHECK_EQ(state_, kPaused);
   DCHECK(!flush_cb_.is_null());
 
-  audio_time_buffered_ = kNoTimestamp();
-  current_time_ = kNoTimestamp();
-  received_end_of_stream_ = false;
-  rendered_end_of_stream_ = false;
-  preroll_aborted_ = false;
-
-  earliest_end_time_ = now_cb_.Run();
-  splicer_->Reset();
-  algorithm_->FlushBuffers();
+  {
+    base::AutoLock auto_lock(lock_);
+    audio_time_buffered_ = kNoTimestamp();
+    current_time_ = kNoTimestamp();
+    received_end_of_stream_ = false;
+    rendered_end_of_stream_ = false;
+    preroll_aborted_ = false;
+
+    earliest_end_time_ = now_cb_.Run();
+    splicer_->Reset();
+    algorithm_->FlushBuffers();
+  }
 
   base::ResetAndReturn(&flush_cb_).Run();
 }
 
+void AudioRendererImpl::StopDecoderDone() {
+  if (state_ == kStopped)
+    return;
+
+  DCHECK(!stop_cb_.is_null());
+  DCHECK(init_cb_.is_null());
+
+  {
+    base::AutoLock auto_lock(lock_);
+    ChangeState_Locked(kStopped);
+    algorithm_.reset();
+    init_cb_.Reset();
+    underflow_cb_.Reset();
+    time_cb_.Reset();
+    flush_cb_.Reset();
+  }
+
+  base::ResetAndReturn(&stop_cb_).Run();
+}
+
 void AudioRendererImpl::Stop(const base::Closure& callback) {
   DCHECK(task_runner_->BelongsToCurrentThread());
   DCHECK(!callback.is_null());
@@ -194,17 +216,16 @@ void AudioRendererImpl::Stop(const base::Closure& callback) {
     sink_ = NULL;
   }
 
-  {
-    base::AutoLock auto_lock(lock_);
-    ChangeState_Locked(kStopped);
-    algorithm_.reset(NULL);
-    init_cb_.Reset();
-    underflow_cb_.Reset();
-    time_cb_.Reset();
-    flush_cb_.Reset();
+  stop_cb_ = callback;
+
+  if (decoder_) {
+    DCHECK(task_runner_->BelongsToCurrentThread());
+    decoder_->Stop(BindToCurrentLoop(
+        base::Bind(&AudioRendererImpl::StopDecoderDone, weak_this_)));
+    return;
   }
 
-  callback.Run();
+  StopDecoderDone();
 }
 
 void AudioRendererImpl::Preroll(base::TimeDelta time,