[Cast] Software encoder support for varying video frame sizes.

media/cast/sender/video_encoder.h

Index: media/cast/sender/video_encoder.h
diff --git a/media/cast/sender/video_encoder.h b/media/cast/sender/video_encoder.h
index bcb323c12a1fd83fa99cbba0baccf30894e7e0d5..81caff6f365523e378df979a82c880349b4abbad 100644
--- a/media/cast/sender/video_encoder.h
+++ b/media/cast/sender/video_encoder.h
@@ -26,6 +26,10 @@ class VideoEncoder {
 
   virtual ~VideoEncoder() {}
 
+  // Returns true if the size of video frames passed in successive calls to
+  // EncodedVideoFrame() can vary.
+  virtual bool CanEncodeVariedFrameSizes() const;

[hubbe, 2015/01/31 00:55:51]

I think it would be better to make this pure virtual to make sure that people
who extend VideoEncoder don't forget to override this function.

[miu, 2015/01/31 04:53:04]

Done.

+
   // If true is returned, the Encoder has accepted the request and will process
   // it asynchronously, running |frame_encoded_callback| on the MAIN
   // CastEnvironment thread with the result.  If false is returned, nothing