Mark POWER key as system key so that it won't be passed to regular apps.

ui/wm/core/accelerator_delegate.h

 // 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.
 
 #ifndef UI_WM_CORE_ACCELERATOR_DELEGATE_H_
 #define UI_WM_CORE_ACCELERATOR_DELEGATE_H_
 
 namespace ui {
 class Accelerator;
 class KeyEvent;
 }
 
 namespace wm {
 
 class AcceleratorDelegate {
  public:
   virtual ~AcceleratorDelegate() {}
 
-  // Type of keys that triggers accelerators.
-  enum KeyType {
-    KEY_TYPE_SYSTEM,
-    KEY_TYPE_OTHER,
-  };
-
   // Return true if the |accelerator| has been processed.
   virtual bool ProcessAccelerator(const ui::KeyEvent& event,
-                                  const ui::Accelerator& accelerator,
-                                  KeyType key_type) = 0;
+                                  const ui::Accelerator& accelerator) = 0;
 };
 
 }  // namespace wm
 
 #endif  // UI_WM_CORE_ACCELERATOR_DELEGATE_H_