[Cast] Repurpose CastInitializationStatus for variable frame size support.

media/cast/receiver/audio_decoder.h

Index: media/cast/receiver/audio_decoder.h
diff --git a/media/cast/receiver/audio_decoder.h b/media/cast/receiver/audio_decoder.h
index 0b13eae6a8f47cfc3e19030c66e24df7300ba071..a68b6fb9e579f021f9d48a6b2157d516834044e3 100644
--- a/media/cast/receiver/audio_decoder.h
+++ b/media/cast/receiver/audio_decoder.h
@@ -32,10 +32,10 @@ class AudioDecoder {
                Codec codec);
   virtual ~AudioDecoder();
 
-  // Returns STATUS_AUDIO_INITIALIZED if the decoder was successfully
-  // constructed from the given FrameReceiverConfig.  If this method returns any
-  // other value, calls to DecodeFrame() will not succeed.
-  CastInitializationStatus InitializationResult() const;
+  // Returns STATUS_INITIALIZED if the decoder was successfully constructed from
+  // the given FrameReceiverConfig.  If this method returns any other value,
+  // calls to DecodeFrame() will not succeed.
+  OperationalStatus InitializationResult() const;
 
   // Decode the payload in |encoded_frame| asynchronously.  |callback| will be
   // invoked on the CastEnvironment::MAIN thread with the result.