[Mac] Factor out keyboard shortcut handling from ChromeEventProcessingWindow.

ui/views/cocoa/native_widget_mac_nswindow.h

Index: ui/views/cocoa/native_widget_mac_nswindow.h
diff --git a/ui/views/cocoa/native_widget_mac_nswindow.h b/ui/views/cocoa/native_widget_mac_nswindow.h
index 943c3e20735d0b2c106bb6c698070572f6f1a950..8886654763e82f5d8ce9c50a234467148a9786f0 100644
--- a/ui/views/cocoa/native_widget_mac_nswindow.h
+++ b/ui/views/cocoa/native_widget_mac_nswindow.h
@@ -7,12 +7,16 @@
 
 #import <Cocoa/Cocoa.h>
 
+#import "ui/base/cocoa/command_dispatcher.h"
 #include "ui/views/views_export.h"
 
 // The NSWindow used by BridgedNativeWidget. Provides hooks into AppKit that
 // can only be accomplished by overriding methods.
 VIEWS_EXPORT
-@interface NativeWidgetMacNSWindow : NSWindow
+@interface NativeWidgetMacNSWindow : NSWindow<CommandDispatchingWindow> {
+ @private
+  base::scoped_nsobject<CommandDispatcher> commandDispatcher_;
+}
 @end
 
 #endif  // UI_VIEWS_COCOA_NATIVE_WIDGET_MAC_NSWINDOW_H_