Remove all uses of toolkit_use_gtk in the gyp files.

ui/views/metrics_aura.cc

 // Copyright (c) 2011 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/metrics.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 #endif
 
 namespace {
 
 // Default double click interval in milliseconds.
-// Same as what gtk uses.
 const int kDefaultDoubleClickInterval = 500;
 
 }  // namespace
 
 namespace views {
 
 int GetDoubleClickInterval() {
 #if defined(OS_WIN)
   return ::GetDoubleClickTime();
 #else
   // TODO(jennyz): This value may need to be adjusted on different platforms.
   return kDefaultDoubleClickInterval;
 #endif
 }
 
 int GetMenuShowDelay() {
 #if defined(OS_WIN)
   static DWORD delay = 0;
   if (!delay && !SystemParametersInfo(SPI_GETMENUSHOWDELAY, 0, &delay, 0))
     delay = kDefaultMenuShowDelay;
   return delay;
 #else
   return 0;
 #endif
 }
 
 }  // namespace views