Require Renderer::Initialize() to return a status code via callback.

media/base/video_renderer.h

Index: media/base/video_renderer.h
diff --git a/media/base/video_renderer.h b/media/base/video_renderer.h
index 94196eb45996da3d5c6b251b61cabc48d2aede54..1e4433323e6c0bcf3fcafe0b8d365f4ad111b040 100644
--- a/media/base/video_renderer.h
+++ b/media/base/video_renderer.h
@@ -33,7 +33,8 @@ class MEDIA_EXPORT VideoRenderer {
   virtual ~VideoRenderer();
 
   // Initializes a VideoRenderer with |stream|, executing |init_cb| upon
-  // completion.
+  // completion. If initialization fails, only |init_cb| (not |error_cb|) will
+  // be called.
   //
   // |set_decryptor_ready_cb| is fired when a Decryptor is needed, i.e. when the
   // |stream| is encrypted.
@@ -49,7 +50,7 @@ class MEDIA_EXPORT VideoRenderer {
   //
   // |ended_cb| is executed when video rendering has reached the end of stream.
   //
-  // |error_cb| is executed if an error was encountered.
+  // |error_cb| is executed if an error was encountered after initialization.
   //
   // |get_time_cb| is used to query the current media playback time.
   virtual void Initialize(DemuxerStream* stream,