Chromecast: adds interfaces for hardware layer of CMA pipeline.

chromecast/media/cma/backend/media_clock_device.cc

Index: chromecast/media/cma/backend/media_clock_device.cc
diff --git a/chromecast/media/cma/backend/media_clock_device.cc b/chromecast/media/cma/backend/media_clock_device.cc
new file mode 100644
index 0000000000000000000000000000000000000000..853e5bafbd0cdd1ae12575a517371700e0c5f4c4
--- /dev/null
+++ b/chromecast/media/cma/backend/media_clock_device.cc
@@ -0,0 +1,55 @@
+// 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.
+
+#include "chromecast/media/cma/backend/media_clock_device.h"
+
+#include "base/logging.h"
+
+namespace chromecast {
+namespace media {
+
+MediaClockDevice::MediaClockDevice() {
+}
+
+MediaClockDevice::~MediaClockDevice() {
+}
+
+// static
+bool MediaClockDevice::IsValidStateTransition(State state1, State state2) {
+  if (state2 == state1)
+    return true;
+
+  // All states can transition to |kStateError|.
+  bool is_transition_valid = (state2 == kStateError);
+
+  // All the other valid FSM transitions.
+  is_transition_valid = is_transition_valid ||
+      (state1 == kStateUninitialized && (state2 == kStateIdle)) ||
+      (state1 == kStateIdle && (state2 == kStateRunning ||
+                                state2 == kStateUninitialized)) ||
+      (state1 == kStateRunning && (state2 == kStateIdle)) ||
+      (state1 == kStateError && (state2 == kStateUninitialized));
+
+  return is_transition_valid;
+}
+
+// static
+std::string MediaClockDevice::StateToString(const State& state) {
+  switch (state) {
+    case kStateUninitialized:
+      return "Uninitialized";
+    case kStateIdle:
+      return "Idle";
+    case kStateRunning:
+      return "Running";
+    case kStateError:
+      return "Error";
+    default:
+      NOTREACHED() << "Unknown MediaClockDevice::State: " << state;
+      return "";
+  }
+}
+
+}  // namespace media
+}  // namespace chromecast