Implement pinch-zoom scaling for main-frame scrollbars and pinch-zoom overlay scrollbars.

cc/cc.gyp

 # Copyright (c) 2012 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.
 
 {
   'variables': {
     'cc_source_files': [
       'animation.cc',
       'animation.h',
       'animation_curve.cc',
@@ skipping 151 matching lines @@
       'picture_layer_tiling.cc',
       'picture_layer_tiling.h',
       'picture_layer_tiling_set.cc',
       'picture_layer_tiling_set.h',
       'picture_pile.cc',
       'picture_pile.h',
       'picture_pile_base.cc',
       'picture_pile_base.h',
       'picture_pile_impl.cc',
       'picture_pile_impl.h',
+      'pinch_zoom_scrollbar.cc',
+      'pinch_zoom_scrollbar.h',
+      'pinch_zoom_scrollbar_geometry.cc',
+      'pinch_zoom_scrollbar_geometry.h',
+      'pinch_zoom_scrollbar_painter.cc',
+      'pinch_zoom_scrollbar_painter.h',
       'platform_color.h',
       'prioritized_resource.cc',
       'prioritized_resource.h',
       'prioritized_resource_manager.cc',
       'prioritized_resource_manager.h',
       'priority_calculator.cc',
       'priority_calculator.h',
       'program_binding.cc',
       'program_binding.h',
       'proxy.cc',
@@ skipping 178 matching lines @@
         'CC_IMPLEMENTATION=1',
       ],
       'sources': [
         '<@(cc_source_files)',
       ],
       # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
       'msvs_disabled_warnings': [ 4267, ],
     },
   ],
 }