Insert pinch zoom virtual viewport layers to graphics layer tree.

Source/WebKit/chromium/WebKit.gyp

 #
 # Copyright (C) 2011 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #         * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #         * Redistributions in binary form must reproduce the above
@@ skipping 334 matching lines @@
                 'src/painting/ContinuousPainter.h',
                 'src/painting/ContinuousPainter.cpp',
                 'src/painting/PaintAggregator.h',
                 'src/painting/PaintAggregator.cpp',
                 'src/PageOverlay.cpp',
                 'src/PageOverlay.h',
                 'src/PageOverlayList.cpp',
                 'src/PageOverlayList.h',
                 'src/PageWidgetDelegate.cpp',
                 'src/PageWidgetDelegate.h',
+                'src/PinchViewports.cpp',
+                'src/PinchViewports.h',
                 'src/PopupContainer.cpp',
                 'src/PopupContainer.h',
                 'src/PopupMenuChromium.cpp',
                 'src/PopupMenuChromium.h',
                 'src/PopupListBox.cpp',
                 'src/PopupListBox.h',
                 'src/ScrollbarGroup.cpp',
                 'src/ScrollbarGroup.h',
                 'src/SharedWorkerRepository.cpp',
                 'src/SourceBufferPrivateImpl.cpp',
@@ skipping 415 matching lines @@
         ['clang==1', {
             'target_defaults': {
                 'cflags': ['-Wglobal-constructors'],
                 'xcode_settings': {
                     'WARNING_CFLAGS': ['-Wglobal-constructors'],
                 },
             },
         }],
     ], # conditions
 }