Decouple 'give me more data' and 'rendered end of stream' audio callbacks.

content/renderer/media/audio_renderer_impl.h

Index: content/renderer/media/audio_renderer_impl.h
===================================================================
--- content/renderer/media/audio_renderer_impl.h	(revision 120523)
+++ content/renderer/media/audio_renderer_impl.h	(working copy)
@@ -19,6 +19,7 @@
 
 #include <vector>
 
+#include "base/atomicops.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/synchronization/lock.h"
@@ -77,12 +78,19 @@
   void DoPause();
   void DoSeek();
 
+  // Methods called on IO thread ----------------------------------------------
+  void DoSignalEndOfStream(base::subtle::AtomicWord stream_id);
+
   // media::AudioRendererSink::RenderCallback implementation.
   virtual size_t Render(const std::vector<float*>& audio_data,
                         size_t number_of_frames,
                         size_t audio_delay_milliseconds) OVERRIDE;
   virtual void OnError() OVERRIDE;
 
+  // Returns delay in ms before call to OnRenderEndOfStream().
+  // Made virtual so test can override.
+  virtual int64 OnRenderEndOfStreamDelay();
+
   // Accessors used by tests.
   base::Time earliest_end_time() const {
     return earliest_end_time_;
@@ -113,6 +121,9 @@
   // Set to true when OnInitialize() is called.
   bool is_initialized_;
 
+  // Set to true when we post delayed task to signal 'ended' event.
+  bool ended_event_scheduled_;
+
   // We're supposed to know amount of audio data OS or hardware buffered, but
   // that is not always so -- on my Linux box
   // AudioBuffersState::hardware_delay_bytes never reaches 0.
@@ -131,6 +142,19 @@
 
   AudioParameters audio_parameters_;
 
+  // Use message loop proxy, not message loop itself, to avoid crash
+  // because of message loop that ended while we are still playing.
+  // We don't need complex shutdown operations, just not posting tasks
+  // is enough, so we can use message loop proxy.
+  scoped_refptr<base::MessageLoopProxy> io_message_loop_proxy_;
+
+  // Stream id -- necessary because there is no way to cancel scheduled task.
+  // We want be sure we are still playing the same stream when delayed task is
+  // called. If seek or pause happened after scheduling but before task was
+  // called, there would be mismatch between expected and actual ids and delayed
+  // task would not do anything.
+  base::subtle::AtomicWord stream_id_;
+
   DISALLOW_COPY_AND_ASSIGN(AudioRendererImpl);
 };