Remove all uses of toolkit_use_gtk in the gyp files.

ui/views/view_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/view.h"
 
 namespace {
 
 // Default horizontal drag threshold in pixels.
-// Same as what gtk uses.
 const int kDefaultHorizontalDragThreshold = 8;
 
 // Default vertical drag threshold in pixels.
-// Same as what gtk uses.
 const int kDefaultVerticalDragThreshold = 8;
 
 }  // namespace
 
 namespace views {
 
 int View::GetHorizontalDragThreshold() {
   // TODO(jennyz): This value may need to be adjusted for different platforms
   // and for different display density.
   return kDefaultHorizontalDragThreshold;
 }
 
 int View::GetVerticalDragThreshold() {
   // TODO(jennyz): This value may need to be adjusted for different platforms
   // and for different display density.
   return kDefaultVerticalDragThreshold;
 }
 
 }  // namespace views