Add support for Command key for Extension Commands

ui/base/accelerators/accelerator.h

 // Copyright (c) 2012 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.
 
 // This class describe a keyboard accelerator (or keyboard shortcut).
 // Keyboard accelerators are registered with the FocusManager.
 // It has a copy constructor and assignment operator so that it can be copied.
 // It also defines the < operator so that it can be used as a key in a std::map.
 //
 
@@ skipping 31 matching lines @@
   // Sets the event type if the accelerator should be processed on an event
   // other than ui::ET_KEY_PRESSED.
   void set_type(ui::EventType type) { type_ = type; }
   ui::EventType type() const { return type_; }
 
   int modifiers() const { return modifiers_; }
 
   bool IsShiftDown() const;
   bool IsCtrlDown() const;
   bool IsAltDown() const;
+  bool IsCmdDown() const;
 
   // Returns a string with the localized shortcut if any.
   string16 GetShortcutText() const;
 
  protected:
   // The keycode (VK_...).
   KeyboardCode key_code_;
 
   // The event type (usually ui::ET_KEY_PRESSED).
   EventType type_;
@@ skipping 28 matching lines @@
   virtual bool GetAcceleratorForCommandId(int command_id,
                                           ui::Accelerator* accelerator) = 0;
 
  protected:
   virtual ~AcceleratorProvider() {}
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_ACCELERATORS_ACCELERATOR_H_