Notify HTMLMediaElement when media pipeline init has finished

media/filters/pipeline_controller.h

Index: media/filters/pipeline_controller.h
diff --git a/media/filters/pipeline_controller.h b/media/filters/pipeline_controller.h
index 4c2a70f7f8e55c90b41515416d325527728b549b..d172d46172bf3e7725ff3321ace8fcf28f75de29 100644
--- a/media/filters/pipeline_controller.h
+++ b/media/filters/pipeline_controller.h
@@ -46,12 +46,15 @@ class MEDIA_EXPORT PipelineController {
   // outlive the resulting PipelineController. The callbacks are:
   //   - |renderer_factory_cb| is called by PipelineController to create new
   //     renderers when starting and resuming.
+  //   - |start_done_cb| is called when the pipeline has finished the async
+  //     start operation either successfully or unsuccessfully.
   //   - |seeked_cb| is called upon reaching a stable state if a seek occured.
   //   - |suspended_cb| is called immediately after suspendeding.
   //   - |error_cb| is called if any operation on |pipeline_| does not result
   //     in PIPELINE_OK or its error callback is called.
   PipelineController(Pipeline* pipeline,
                      const RendererFactoryCB& renderer_factory_cb,
+                     const PipelineStatusCB& start_done_cb,
                      const SeekedCB& seeked_cb,
                      const SuspendedCB& suspended_cb,
                      const PipelineStatusCB& error_cb);
@@ -115,6 +118,9 @@ class MEDIA_EXPORT PipelineController {
   // Factory for Renderers, used for Start() and Resume().
   RendererFactoryCB renderer_factory_cb_;
 
+  // Called when Pipeline::Start is completed.
+  PipelineStatusCB start_done_cb_;
+
   // Called after seeks (which includes Start()) upon reaching a stable state.
   // Multiple seeks result in only one callback if no stable state occurs
   // between them.