Load CMA backend from shared library

chromecast/public/media/media_clock_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_PUBLIC_MEDIA_MEDIA_CLOCK_DEVICE_H_
+#define CHROMECAST_PUBLIC_MEDIA_MEDIA_CLOCK_DEVICE_H_
+
+#include <string>
+
+namespace chromecast {
+namespace media {
+
+// Interface for platform-specific pipeline clock.
+// Pipeline clocks follow this state machine:
+//                      -------------------
+//                      |                 |
+//                      v                 |
+// kUninitialized --> kIdle  --------- kRunning
+//
+// {any state} --> kError
+//
+// Notes:
+// - Hardware resources should be acquired when transitioning from the
+//   |kUninitialized| state to the |kIdle| state.
+// - The initial value of the timeline will only be set in the kIdle state.
+class MediaClockDevice {
+ public:
+  enum State {
+    kStateUninitialized,
+    kStateIdle,
+    kStateRunning,
+    kStateError,
+  };
+
+  virtual ~MediaClockDevice() {}
+
+  // Returns the current state of the media clock.
+  virtual State GetState() const = 0;
+
+  // Changes the state and performs any necessary transitions.
+  // Returns true when successful.
+  virtual bool SetState(State new_state) = 0;
+
+  // Sets the initial value of the timeline in microseconds.
+  // Will only be invoked in state kStateIdle.
+  // Returns true when successful.
+  virtual bool ResetTimeline(int64_t time_microseconds) = 0;
+
+  // Sets the clock rate.
+  // |rate| == 0 means the clock is not progressing and that the renderer
+  // tied to this media clock should pause rendering.
+  // Will only be invoked in states kStateIdle or kStateRunning.
+  virtual bool SetRate(float rate) = 0;
+
+  // Retrieves the media clock time in microseconds.
+  // Will only be invoked in states kStateIdle or kStateRunning.
+  virtual int64_t GetTime() = 0;

[servolk, 2015/07/30 17:50:29]

Now that it returns just int64_t, let's rename it into GetTimeMicroseconds to
make it clear what value is being returned.

[halliwell, 2015/07/30 18:20:18]

Done.

+};
+
+}  // namespace media
+}  // namespace chromecast
+
+#endif  // CHROMECAST_MEDIA_CMA_BACKEND_MEDIA_CLOCK_DEVICE_H_