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

ash/accelerators/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 ASH_ACCELERATORS_ACCELERATOR_DELEGATE_H_
 #define ASH_ACCELERATORS_ACCELERATOR_DELEGATE_H_
 
 #include "ash/ash_export.h"
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 #include "ui/wm/core/accelerator_delegate.h"
 
 namespace ash {
 
 class ASH_EXPORT AcceleratorDelegate
     : NON_EXPORTED_BASE(public ::wm::AcceleratorDelegate) {
  public:
   AcceleratorDelegate();
   ~AcceleratorDelegate() override;
 
   // wm::AcceleratorDelegate:
   bool ProcessAccelerator(const ui::KeyEvent& event,
-                          const ui::Accelerator& accelerator,
-                          KeyType key_type) override;
+                          const ui::Accelerator& accelerator) override;
 
  private:
   // Returns true if the window should be allowed a chance to handle
   // system keys.
   bool CanConsumeSystemKeys(const ui::KeyEvent& event);
 
   bool ShouldProcessAcceleratorNow(const ui::KeyEvent& event,
                                    const ui::Accelerator& accelerator);
 
   DISALLOW_COPY_AND_ASSIGN(AcceleratorDelegate);
 };
 
 }  // namespace ash
 
 #endif  // ASH_ACCELERATORS_ACCELERATOR_DELEGATE_H_