chromeos: Add support for the battery status API on chromeos.

content/browser/battery_status/battery_status_message_filter.cc

+// Copyright (c) 2012 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/browser/battery_status/battery_status_message_filter.h"
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "content/browser/battery_status/battery_status_provider_impl.h"
+#include "content/common/battery_status_messages.h"
+#include "content/public/browser/power_supply_status.h"
+#include "third_party/WebKit/Source/WebKit/chromium/public/WebBatteryStatus.h"
+
+namespace content {
+
+class BatteryStatusMessageFilter::PowerManagerObserver :
+    public BatteryStatusProviderImpl::Observer {
+ public:
+  explicit PowerManagerObserver(BatteryStatusMessageFilter* filter)
+      : filter_(filter) {
+    BatteryStatusProviderImpl::GetInstance()->AddObserver(this);
+  }
+
+  virtual ~PowerManagerObserver() {
+    BatteryStatusProviderImpl::GetInstance()->RemoveObserver(this);
+  }
+
+  void DestroyOnUI() {
+    filter_ = NULL;
+    BrowserThread::DeleteOnUIThread::Destruct(this);
+  }
+
+ private:
+  virtual void PowerChanged(
+      const PowerSupplyStatus& power_status) OVERRIDE {
+    if (filter_)
+      filter_->SendUpdates(power_status);
+  }
+
+  BatteryStatusMessageFilter* filter_;
+
+  DISALLOW_COPY_AND_ASSIGN(PowerManagerObserver);
+};
+
+BatteryStatusMessageFilter::BatteryStatusMessageFilter() {
+}
+
+void BatteryStatusMessageFilter::SendUpdates(
+    const PowerSupplyStatus& power_status) {
+  WebKit::WebBatteryStatus web_status;
+  web_status.charging = power_status.line_power_on;
+  web_status.chargingTime = power_status.battery_seconds_to_full;
+  web_status.dischargingTime = power_status.battery_seconds_to_empty;
+  web_status.level = power_status.battery_percentage / 100.;
+
+  Send(new BatteryStatusMsg_Updated(web_status));
+}
+
+BatteryStatusMessageFilter::~BatteryStatusMessageFilter() {
+  if (observer_.get()) {
+    // This destructor is in the IO thread. But we need to destroy the observer
+    // in the UI thread.
+    observer_.release()->DestroyOnUI();
+  }
+}
+
+void BatteryStatusMessageFilter::OnStartUpdating() {
+  if (!observer_.get())
+    observer_.reset(new PowerManagerObserver(this));
+}
+
+void BatteryStatusMessageFilter::OnStopUpdating() {
+  observer_.reset();
+}
+
+void BatteryStatusMessageFilter::OverrideThreadForMessage(
+    const IPC::Message& message,
+    BrowserThread::ID* thread) {
+  if (IPC_MESSAGE_CLASS(message) == BatteryStatusMsgStart)
+    *thread = BrowserThread::UI;
+}
+
+bool BatteryStatusMessageFilter::OnMessageReceived(const IPC::Message& message,
+                                                   bool* message_was_ok) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP_EX(BatteryStatusMessageFilter, message, *message_was_ok)
+    IPC_MESSAGE_HANDLER(BatteryStatusHostMsg_StartUpdating, OnStartUpdating)
+    IPC_MESSAGE_HANDLER(BatteryStatusHostMsg_StopUpdating, OnStopUpdating)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP_EX()
+  return handled;
+}
+
+}  // namespace content