Add support to Battery Status API in blink.

Source/modules/battery/BatteryManager.idl

Index: Source/modules/battery/BatteryManager.idl
diff --git a/Source/modules/battery/BatteryManager.idl b/Source/modules/battery/BatteryManager.idl
new file mode 100644
index 0000000000000000000000000000000000000000..7cc5451be03d08c6239dde793ec97e5d43c47bc0
--- /dev/null
+++ b/Source/modules/battery/BatteryManager.idl
@@ -0,0 +1,22 @@
+// 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.
+
+// http://dev.w3.org/2009/dap/system-info/battery-status.html
+[
+    NoInterfaceObject,
+    ActiveDOMObject,
+    RuntimeEnabled=BatteryStatus,
+] interface BatteryManager : EventTarget {
+    readonly attribute boolean charging;
+    readonly attribute double chargingTime;
+    readonly attribute double dischargingTime;
+    readonly attribute double level;

[abarth-chromium, 2014/02/28 06:45:14]

I suspect we'll want to remove these properties as discussed earlier, but we can
include them for now.

+
+    attribute EventHandler onchargingchange;
+    attribute EventHandler onchargingtimechange;
+    attribute EventHandler ondischargingtimechange;
+    attribute EventHandler onlevelchange;
+
+};
+