Add Battery Status API support in content/renderer and IPC messages.

content/renderer/battery_status/battery_status_dispatcher.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 CONTENT_RENDERER_BATTERY_STATUS_BATTERY_STATUS_DISPATCHER_H_
+#define CONTENT_RENDERER_BATTERY_STATUS_BATTERY_STATUS_DISPATCHER_H_
+
+#include "content/public/renderer/render_process_observer.h"
+
+namespace blink {
+class WebBatteryStatus;
+class WebBatteryStatusListener;
+}
+
+namespace content {
+class RenderThread;
+
+class CONTENT_EXPORT BatteryStatusDispatcher : public RenderProcessObserver {
+ public:
+  BatteryStatusDispatcher();
+  virtual ~BatteryStatusDispatcher();
+
+  void Attach(RenderThread* thread);
+  virtual bool OnControlMessageReceived(const IPC::Message& message) OVERRIDE;

[jochen (gone - plz use gerrit), 2014/04/30 04:54:07]

please group overrides and add a comment which interface they implement

[timvolodine, 2014/05/01 10:32:39]

Done.

+
+  // Sets the listener to receive battery status updates. Returns true if the
+  // registration was successful.
+  bool SetListener(blink::WebBatteryStatusListener* listener);
+
+ private:
+  virtual bool Start();

[jochen (gone - plz use gerrit), 2014/04/30 04:54:07]

i guess your test needs to be a friend of this class, or those methods should be
protected?

[timvolodine, 2014/05/01 10:32:39]

Done.

+  virtual bool Stop();
+  void OnDidChange(const blink::WebBatteryStatus& status);
+
+  blink::WebBatteryStatusListener* listener_;
+};

[jochen (gone - plz use gerrit), 2014/04/30 04:54:07]

disallow copy & assign

[timvolodine, 2014/05/01 10:32:39]

Done.

+
+}  // namespace content
+
+#endif  // CONTENT_RENDERER_BATTERY_STATUS_BATTERY_STATUS_DISPATCHER_H_