Created multi-process-friendly PowerMonitor interface.

content/child/power_monitor_broadcast_source.cc

+// 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.
+
+#include "content/child/power_monitor_broadcast_source.h"
+
+#include "content/common/power_monitor_messages.h"
+
+namespace content {
+
+PowerMonitorBroadcastSource::PowerMonitorBroadcastSource(
+    scoped_refptr<base::MessageLoopProxy> message_loop)
+    : last_reported_battery_power_state_(false),
+      weak_factory_(this) {
+  message_filter_ = new PowerMessageFilter(weak_factory_.GetWeakPtr(),
+      message_loop);
+}
+
+PowerMonitorBroadcastSource::~PowerMonitorBroadcastSource() {
+}
+
+IPC::ChannelProxy::MessageFilter*
+PowerMonitorBroadcastSource::MessageFilter() {
+  return message_filter_.get();
+}
+
+bool PowerMonitorBroadcastSource::IsOnBatteryPowerImpl() {
+  return last_reported_battery_power_state_;
+}
+
+void PowerMonitorBroadcastSource::OnPowerStateChange(bool on_battery_power) {
+  last_reported_battery_power_state_ = on_battery_power;
+  ProcessPowerEvent(PowerMonitorSource::POWER_STATE_EVENT);
+}
+
+void PowerMonitorBroadcastSource::OnSuspend() {
+  ProcessPowerEvent(PowerMonitorSource::SUSPEND_EVENT);
+}
+
+void PowerMonitorBroadcastSource::OnResume() {
+  ProcessPowerEvent(PowerMonitorSource::RESUME_EVENT);
+}
+
+PowerMonitorBroadcastSource::PowerMessageFilter::PowerMessageFilter(
+    base::WeakPtr<PowerMonitorBroadcastSource> source,
+    scoped_refptr<base::MessageLoopProxy> message_loop)
+    : source_(source),
+      message_loop_(message_loop) {
+}
+
+PowerMonitorBroadcastSource::PowerMessageFilter::~PowerMessageFilter() {
+}
+
+bool PowerMonitorBroadcastSource::PowerMessageFilter::OnMessageReceived(
+    const IPC::Message& message) {
+  bool msg_is_ok = false;
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP_EX(PowerMessageFilter, message, msg_is_ok)
+    IPC_MESSAGE_HANDLER(PowerMonitorMsg_PowerStateChange, OnPowerStateChange)
+    IPC_MESSAGE_HANDLER(PowerMonitorMsg_Suspend, OnSuspend)
+    IPC_MESSAGE_HANDLER(PowerMonitorMsg_Resume, OnResume)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP_EX()
+  return handled && msg_is_ok;

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

nit: take out the msg_is_ok stuff. this is only needed in the browser, and in
which case we kill the child process. it's not need here since the browser is
trusted. also, OnMessageHandled should return true if it takes the IPC,
irrespective of whether there was a problem parsing it or not

+}
+
+void PowerMonitorBroadcastSource::PowerMessageFilter::OnPowerStateChange(
+    bool on_battery_power) {
+  message_loop_->PostTask(FROM_HERE,
+      base::Bind(&PowerMonitorBroadcastSource::OnPowerStateChange, source_,
+          on_battery_power));
+}
+
+void PowerMonitorBroadcastSource::PowerMessageFilter::OnSuspend() {
+  message_loop_->PostTask(FROM_HERE,
+      base::Bind(&PowerMonitorBroadcastSource::OnSuspend, source_));
+}
+
+void PowerMonitorBroadcastSource::PowerMessageFilter::OnResume() {
+  message_loop_->PostTask(FROM_HERE,
+      base::Bind(&PowerMonitorBroadcastSource::OnResume, source_));
+}
+
+}  // namespace content