Load CMA backend from shared library

chromecast/public/media/media_pipeline_backend.h

Index: chromecast/public/media/media_pipeline_backend.h
diff --git a/chromecast/public/media/media_pipeline_backend.h b/chromecast/public/media/media_pipeline_backend.h
new file mode 100644
index 0000000000000000000000000000000000000000..cf64acce20882ecb004c6bc5f3af8a854b804f53
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+++ b/chromecast/public/media/media_pipeline_backend.h
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+// Copyright 2015 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_PUBLIC_MEDIA_MEDIA_PIPELINE_BACKEND_H_
+#define CHROMECAST_PUBLIC_MEDIA_MEDIA_PIPELINE_BACKEND_H_
+
+namespace chromecast {
+namespace media {
+
+class AudioPipelineDevice;
+class MediaClockDevice;
+struct MediaPipelineDeviceParams;
+class VideoPipelineDevice;
+
+// Interface for creating and managing ownership of platform-specific clock,
+// audio and video devices.  cast_shell owns the MediaPipelineBackend for
+// as long as it is needed; the implementation is responsible for
+// tearing down the individual components correctly when it is destroyed.
+// A new MediaPipelineBackend will be instantiated for each media player
+// instance.
+class MediaPipelineBackend {
+ public:
+  virtual ~MediaPipelineBackend() {}
+
+  // Returns the platform-specific pipeline clock.
+  virtual MediaClockDevice* GetClock() = 0;
+
+  // Returns the platform-specific audio backend.
+  virtual AudioPipelineDevice* GetAudio() = 0;
+
+  // Returns the platform-specific video backend.
+  virtual VideoPipelineDevice* GetVideo() = 0;
+};
+
+}  // namespace media
+}  // namespace chromecast
+
+#endif  // CHROMECAST_MEDIA_CMA_BACKEND_MEDIA_PIPELINE_DEVICE_FACTORY_H_