Make base::PowerMonitor work on Chrome OS.

On Chrome OS, updates about the system power status are
received via D-Bus messages on the UI thread. Being in
base/, PowerMonitor can't depend on the code in chromeos/
that receives those messages, so make the Chrome OS code
instead notify PowerMonitor when it receives updates.

BUG=326534

Review URL: https://codereview.chromium.org/622693004

Cr-Commit-Position: refs/heads/master@{#298367}

2 files changed, 50 insertions, 0 deletions

diff --git a/base/power_monitor/power_monitor_device_source.h b/base/power_monitor/power_monitor_device_source.h
index 37b065a..d29ec0a 100644
--- a/base/power_monitor/power_monitor_device_source.h
+++ b/base/power_monitor/power_monitor_device_source.h
@@ -51,6 +51,16 @@ class BASE_EXPORT PowerMonitorDeviceSource : public PowerMonitorSource {
 #endif  // OS_IOS
 #endif  // OS_MACOSX
 
+#if defined(OS_CHROMEOS)
+  // On Chrome OS, Chrome receives power-related events from powerd, the system
+  // power daemon, via D-Bus signals received on the UI thread. base can't
+  // directly depend on that code, so this class instead exposes static methods
+  // so that events can be passed in.
+  static void SetPowerSource(bool on_battery);
+  static void HandleSystemSuspending();
+  static void HandleSystemResumed();
+#endif
+
  private:
 #if defined(OS_WIN)
   // Represents a message-only window for power message handling on Windows.
diff --git a/base/power_monitor/power_monitor_device_source_chromeos.cc b/base/power_monitor/power_monitor_device_source_chromeos.cc
new file mode 100644
index 0000000..c3466ee
--- /dev/null
+++ b/base/power_monitor/power_monitor_device_source_chromeos.cc
@@ -0,0 +1,40 @@
+// 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 "base/power_monitor/power_monitor.h"
+#include "base/power_monitor/power_monitor_device_source.h"
+#include "base/power_monitor/power_monitor_source.h"
+
+namespace base {
+
+namespace {
+
+// The most-recently-seen power source.
+bool g_on_battery = false;
+
+}  // namespace
+
+// static
+void PowerMonitorDeviceSource::SetPowerSource(bool on_battery) {
+  if (on_battery != g_on_battery) {
+    g_on_battery = on_battery;
+    ProcessPowerEvent(POWER_STATE_EVENT);
+  }
+}
+
+// static
+void PowerMonitorDeviceSource::HandleSystemSuspending() {
+  ProcessPowerEvent(SUSPEND_EVENT);
+}
+
+// static
+void PowerMonitorDeviceSource::HandleSystemResumed() {
+  ProcessPowerEvent(RESUME_EVENT);
+}
+
+bool PowerMonitorDeviceSource::IsOnBatteryPowerImpl() {
+  return g_on_battery;
+}
+
+}  // namespace base