Load CMA backend from shared library

chromecast/media/cma/backend/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_MEDIA_CMA_BACKEND_MEDIA_CLOCK_DEVICE_H_
-#define CHROMECAST_MEDIA_CMA_BACKEND_MEDIA_CLOCK_DEVICE_H_
-
-#include <string>
-
-#include "base/basictypes.h"
-#include "base/macros.h"
-#include "base/threading/non_thread_safe.h"
-#include "base/time/time.h"
-
-namespace chromecast {
-namespace media {
-
-// MediaClockDevice -
-//
-// State machine:
-//                      -------------------
-//                      |                 |
-//                      v                 |
-// kUninitialized --> kIdle  --------- kRunning
-//
-// {any state} --> kError
-//
-// Notes:
-// - Hardware resources are acquired when transitioning from the
-//   |kUninitialized| state to the |kIdle| state.
-// - The initial value of the timeline can only be set in the kIdle state.
-//
-class MediaClockDevice
-    : NON_EXPORTED_BASE(public base::NonThreadSafe) {
- public:
-  enum State {
-    kStateUninitialized,
-    kStateIdle,
-    kStateRunning,
-    kStateError,
-  };
-
-  // Return true if transition from |state1| to |state2| is a valid state
-  // transition.
-  static bool IsValidStateTransition(State state1, State state2);
-
-  // Returns string representation of state (for logging)
-  static std::string StateToString(const State& state);
-
-  MediaClockDevice();
-  virtual ~MediaClockDevice();
-
-  // Return 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.
-  // Can only be invoked in state kStateIdle.
-  // Returns true when successful.
-  virtual bool ResetTimeline(base::TimeDelta time) = 0;
-
-  // Sets the clock rate.
-  // Setting it to 0 means the clock is not progressing and that the renderer
-  // tied to this media clock should pause rendering.
-  // Can only be invoked in states kStateIdle or kStateRunning.
-  virtual bool SetRate(float rate) = 0;
-
-  // Retrieves the media clock time.
-  // Can only be invoked in states kStateIdle or kStateRunning.
-  virtual base::TimeDelta GetTime() = 0;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(MediaClockDevice);
-};
-
-}  // namespace media
-}  // namespace chromecast
-
-#endif  // CHROMECAST_MEDIA_CMA_BACKEND_MEDIA_CLOCK_DEVICE_H_