Created multi-process-friendly PowerMonitor interface.

content/child/power_monitor_broadcast_source.h

+// Copyright (c) 2013 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_COMMON_POWER_MONITOR_BROADCAST_SOURCE_H_

[scottmg, 2013/07/30 23:52:53]

nit; header guard CONTENT_CHILD_...

+#define CONTENT_COMMON_POWER_MONITOR_BROADCAST_SOURCE_H_
+
+#include "base/memory/weak_ptr.h"
+#include "base/message_loop/message_loop.h"
+#include "base/power_monitor/power_monitor_source.h"
+#include "content/common/content_export.h"
+#include "ipc/ipc_channel.h"
+#include "ipc/ipc_channel_proxy.h"
+
+namespace content {
+
+// Receives Power Monitor IPC messages sent from the browser process and relays
+// them to the PowerMonitor of the current process.
+class CONTENT_EXPORT PowerMonitorBroadcastSource :
+    public base::PowerMonitorSource {
+ public:
+  explicit PowerMonitorBroadcastSource(
+      scoped_refptr<base::MessageLoopProxy> message_loop);
+  virtual ~PowerMonitorBroadcastSource();
+
+  IPC::ChannelProxy::MessageFilter* MessageFilter();

[jam, 2013/07/30 23:52:00]

nit: GetMessageFilter

+
+ private:
+  friend class PowerMonitorMessageFilter;
+
+  class PowerMessageFilter : public IPC::ChannelProxy::MessageFilter {

[jam, 2013/07/30 23:52:00]

nit: since this is a private class, just move the whole declaration/definition
to the cc file and you can make this header faster to read

+   public:
+    PowerMessageFilter(
+        base::WeakPtr<PowerMonitorBroadcastSource> source,
+        scoped_refptr<base::MessageLoopProxy> message_loop);
+
+    virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
+
+   private:
+    friend class base::RefCounted<PowerMessageFilter>;
+
+    virtual ~PowerMessageFilter();
+
+    void OnPowerStateChange(bool on_battery_power);
+    void OnSuspend();
+    void OnResume();
+
+    base::WeakPtr<PowerMonitorBroadcastSource> source_;
+    scoped_refptr<base::MessageLoopProxy> message_loop_;
+
+    DISALLOW_COPY_AND_ASSIGN(PowerMessageFilter);
+  };
+
+  virtual bool IsOnBatteryPowerImpl() OVERRIDE;
+
+  void OnPowerStateChange(bool on_battery_power);
+  void OnSuspend();
+  void OnResume();
+
+  bool last_reported_battery_power_state_;
+  scoped_refptr<PowerMessageFilter> message_filter_;
+  base::WeakPtrFactory<PowerMonitorBroadcastSource> weak_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(PowerMonitorBroadcastSource);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_POWER_MONITOR_MESSAGE_FILTER_H_