Move chrome.power API from chrome/ to extensions/.

chrome/common/extensions/api/power.idl

-// 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.
-
-// Use the <code>chrome.power</code> API to override the system's power
-// management features.
-namespace power {
-  [noinline_doc] enum Level {
-    // Prevent the system from sleeping in response to user inactivity.
-    system,
-
-    // Prevent the display from being turned off or dimmed or the system
-    // from sleeping in response to user inactivity.
-    display
-  };
-
-  interface Functions {
-    // Requests that power management be temporarily disabled. |level|
-    // describes the degree to which power management should be disabled.
-    // If a request previously made by the same app is still active, it
-    // will be replaced by the new request.
-    static void requestKeepAwake(Level level);
-
-    // Releases a request previously made via requestKeepAwake().
-    static void releaseKeepAwake();
-  };
-};