Load CMA backend from shared library

chromecast/public/media/video_pipeline_device.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#ifndef CHROMECAST_MEDIA_CMA_BACKEND_VIDEO_PIPELINE_DEVICE_H_
-#define CHROMECAST_MEDIA_CMA_BACKEND_VIDEO_PIPELINE_DEVICE_H_
+#ifndef CHROMECAST_PUBLIC_MEDIA_VIDEO_PIPELINE_DEVICE_H_
+#define CHROMECAST_PUBLIC_MEDIA_VIDEO_PIPELINE_DEVICE_H_
 
-#include "base/callback.h"
-#include "base/macros.h"
-#include "chromecast/media/cma/backend/media_component_device.h"
-
-namespace gfx {
-class Size;
-}
+#include "media_component_device.h"
 
 namespace chromecast {
+struct Size;
+
 namespace media {
-class DecoderBufferBase;
 struct VideoConfig;
 
-// VideoPipelineDevice -
+// Interface for platform-specific video pipeline backend.
+// See comments on MediaComponentDevice.
 //
 // Notes:
 // - Like a regular MediaComponentDevice, frames are possibly rendered only
 //   in the kRunning state.
 //   However, the first frame must be rendered regardless of the clock state:
 //   - no synchronization needed to display the first frame,
 //   - the clock rate has no impact on the presentation of the first frame.
-//
 class VideoPipelineDevice : public MediaComponentDevice {
  public:
-  struct VideoClient {
-    VideoClient();
-    ~VideoClient();
-
-    // Invoked each time the natural size is updated.
-    base::Callback<void(const gfx::Size& natural_size)>
-        natural_size_changed_cb;
+  // Callback interface for natural size of video changing.
+  class VideoClient {
+   public:
+    virtual ~VideoClient() {}
+    virtual void OnNaturalSizeChanged(const Size& size) = 0;
   };
 
-  VideoPipelineDevice();
-  ~VideoPipelineDevice() override;
+  ~VideoPipelineDevice() override {}
 
   // Registers |client| as the video specific event handler.
-  virtual void SetVideoClient(const VideoClient& client) = 0;
+  // Implementation takes ownership of |client|.
+  virtual void SetVideoClient(VideoClient* client) = 0;
 
-  // Provide the video configuration.
-  // Must be called before switching from |kStateUninitialized| to |kStateIdle|.
+  // Provides the video configuration.
+  // Called before switching from |kStateUninitialized| to |kStateIdle|.
   // Afterwards, this can be invoked any time the configuration changes.
   // Returns true if the configuration is a supported configuration.
   virtual bool SetConfig(const VideoConfig& config) = 0;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(VideoPipelineDevice);
 };
 
 }  // namespace media
 }  // namespace chromecast
 
 #endif  // CHROMECAST_MEDIA_CMA_BACKEND_VIDEO_PIPELINE_DEVICE_H_