Battery Status API: browser-side implementation.

content/browser/battery_status/battery_status_message_filter.cc

Index: content/browser/battery_status/battery_status_message_filter.cc
diff --git a/content/browser/battery_status/battery_status_message_filter.cc b/content/browser/battery_status/battery_status_message_filter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..19a21b80787290868214061a2f215eef27c4e113
--- /dev/null
+++ b/content/browser/battery_status/battery_status_message_filter.cc
@@ -0,0 +1,56 @@
+// 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 "content/browser/battery_status/battery_status_message_filter.h"
+
+#include "content/common/battery_status_messages.h"
+
+namespace content {
+
+BatteryStatusMessageFilter::BatteryStatusMessageFilter()
+    : BrowserMessageFilter(BatteryStatusMsgStart),
+      is_started_(false) {
+  callback_ = base::Bind(&BatteryStatusMessageFilter::SendBatteryChange,
+                         base::Unretained(this));
+}
+
+BatteryStatusMessageFilter::~BatteryStatusMessageFilter() {
+  DCHECK(BrowserThread::CurrentlyOn(BrowserThread::IO));
+  if (is_started_)
+    subscription_.reset();
+}
+
+bool BatteryStatusMessageFilter::OnMessageReceived(
+    const IPC::Message& message) {
+  bool handled = true;
+  IPC_BEGIN_MESSAGE_MAP(BatteryStatusMessageFilter, message)
+    IPC_MESSAGE_HANDLER(BatteryStatusHostMsg_Start, OnBatteryStatusStart)
+    IPC_MESSAGE_HANDLER(BatteryStatusHostMsg_Stop, OnBatteryStatusStop)
+    IPC_MESSAGE_UNHANDLED(handled = false)
+  IPC_END_MESSAGE_MAP()
+  return handled;
+}
+
+void BatteryStatusMessageFilter::OnBatteryStatusStart() {
+  DCHECK(!is_started_);
+  if (is_started_)
+    return;
+  is_started_ = true;
+  subscription_ = BatteryStatusService::GetInstance()->AddCallback(callback_);
+}
+
+void BatteryStatusMessageFilter::OnBatteryStatusStop() {
+  DCHECK(is_started_);
+  if (!is_started_)
+    return;
+  is_started_ = false;
+  subscription_.reset();
+}
+
+void BatteryStatusMessageFilter::SendBatteryChange(
+    const blink::WebBatteryStatus& status) {
+  Send(new BatteryStatusMsg_DidChange(status));
+}
+
+}  // namespace content