Cast: Flow hw encoder initialization error to extensions API

media/cast/sender/external_video_encoder.h

Index: media/cast/sender/external_video_encoder.h
diff --git a/media/cast/sender/external_video_encoder.h b/media/cast/sender/external_video_encoder.h
index 269fb3e7c88a582744cbfe2a48b2dba840a98600..3a5f73b38eed4caf108972b2d29842980f30b5a2 100644
--- a/media/cast/sender/external_video_encoder.h
+++ b/media/cast/sender/external_video_encoder.h
@@ -28,6 +28,7 @@ class ExternalVideoEncoder : public VideoEncoder {
   ExternalVideoEncoder(
       scoped_refptr<CastEnvironment> cast_environment,
       const VideoSenderConfig& video_config,
+      const CastInitializationCallback& initialization_cb,
       const CreateVideoEncodeAcceleratorCallback& create_vea_cb,
       const CreateVideoEncodeMemoryCallback& create_video_encode_mem_cb);
 
@@ -56,7 +57,9 @@ class ExternalVideoEncoder : public VideoEncoder {
       scoped_refptr<base::SingleThreadTaskRunner> encoder_task_runner);
 
  protected:
-  void EncoderInitialized();
+  // If |success| is true then encoder is initialized successfully.
+  // Otherwise encoder initialization failed.
+  void EncoderInitialized(bool success);
   void EncoderError();
 
  private:
@@ -71,6 +74,8 @@ class ExternalVideoEncoder : public VideoEncoder {
   scoped_refptr<LocalVideoEncodeAcceleratorClient> video_accelerator_client_;
   scoped_refptr<base::SingleThreadTaskRunner> encoder_task_runner_;
 
+  CastInitializationCallback initialization_cb_;
+
   // Weak pointer factory for posting back LocalVideoEncodeAcceleratorClient
   // notifications to ExternalVideoEncoder.
   // NOTE: Weak pointers must be invalidated before all other member variables.