Load CMA backend from shared library

chromecast/media/cma/pipeline/video_pipeline_impl.h

Index: chromecast/media/cma/pipeline/video_pipeline_impl.h
diff --git a/chromecast/media/cma/pipeline/video_pipeline_impl.h b/chromecast/media/cma/pipeline/video_pipeline_impl.h
index 25f875fcf636e0a6d16a46d2af451f09d9eb134a..5a9ea599d320cd38131c02db9a92228a0d54b378 100644
--- a/chromecast/media/cma/pipeline/video_pipeline_impl.h
+++ b/chromecast/media/cma/pipeline/video_pipeline_impl.h
@@ -13,16 +13,13 @@
 #include "chromecast/media/cma/pipeline/video_pipeline_client.h"
 #include "chromecast/public/media/stream_id.h"
 
-namespace gfx {
-class Size;
-}
-
 namespace media {
 class AudioDecoderConfig;
 class VideoDecoderConfig;
 }
 
 namespace chromecast {
+struct Size;
 namespace media {
 class AvPipelineImpl;
 class BrowserCdmCast;
@@ -59,11 +56,14 @@ class VideoPipelineImpl : public VideoPipeline {
   void SetClient(const VideoPipelineClient& client) override;
 
  private:
+  class DeviceClientImpl;
+  friend class DeviceClientImpl;
+
   void OnFlushDone(const ::media::PipelineStatusCB& status_cb);
   void OnUpdateConfig(StreamId id,
                       const ::media::AudioDecoderConfig& audio_config,
                       const ::media::VideoDecoderConfig& video_config);
-  void OnNaturalSizeChanged(const gfx::Size& size);
+  void OnNaturalSizeChanged(const Size& size);
 
   VideoPipelineDevice* video_device_;