[Mac] Factor out keyboard shortcut handling from ChromeEventProcessingWindow.

ui/views/widget/native_widget_mac.mm

 // 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.
 
 #include "ui/views/widget/native_widget_mac.h"
 
 #import <Cocoa/Cocoa.h>
 
 #include "base/mac/foundation_util.h"
 #include "base/mac/scoped_nsobject.h"
@@ skipping 539 matching lines @@
 
 bool NativeWidgetMac::IsTranslucentWindowOpacitySupported() const {
   return false;
 }
 
 void NativeWidgetMac::OnSizeConstraintsChanged() {
   bridge_->OnSizeConstraintsChanged();
 }
 
 void NativeWidgetMac::RepostNativeEvent(gfx::NativeEvent native_event) {
-  NOTIMPLEMENTED();
+  id window = [native_event window];
+  if ([window conformsToProtocol:@protocol(CommandDispatcher)])
+    [window redispatchKeyEvent:native_event];
 }
 
 ////////////////////////////////////////////////////////////////////////////////
 // NativeWidgetMac, protected:
 
 NSWindow* NativeWidgetMac::CreateNSWindow(const Widget::InitParams& params) {
   return [[[NativeWidgetMacNSWindow alloc]
       initWithContentRect:ui::kWindowSizeDeterminedLater
                 styleMask:StyleMaskForParams(params)
                   backing:NSBackingStoreBuffered
@@ skipping 129 matching lines @@
   [[ViewsNSWindowCloseAnimator alloc] initWithWindow:window];
 }
 
 - (void)animationDidEnd:(NSAnimation*)animation {
   [window_ close];
   [animation_ setDelegate:nil];
   [self release];
 }
 
 @end