Refactor cc scrollbar layers to separate solid-color vs desktop.

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': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 136 matching lines @@
         'layers/quad_sink.h',
         'layers/render_pass_sink.h',
         'layers/render_surface.cc',
         'layers/render_surface.h',
         'layers/render_surface_impl.cc',
         'layers/render_surface_impl.h',
         'layers/scrollbar_layer.cc',
         'layers/scrollbar_layer.h',
         'layers/scrollbar_layer_impl.cc',
         'layers/scrollbar_layer_impl.h',
+        'layers/scrollbar_layer_impl_base.cc',
+        'layers/scrollbar_layer_impl_base.h',
+        'layers/scrollbar_layer_interface.h',
         'layers/solid_color_layer.cc',
         'layers/solid_color_layer.h',
         'layers/solid_color_layer_impl.cc',
         'layers/solid_color_layer_impl.h',
+        'layers/solid_color_scrollbar_layer.cc',
+        'layers/solid_color_scrollbar_layer.h',
+        'layers/solid_color_scrollbar_layer_impl.cc',
+        'layers/solid_color_scrollbar_layer_impl.h',
         'layers/texture_layer.cc',
         'layers/texture_layer.h',
         'layers/texture_layer_client.h',
         'layers/texture_layer_impl.cc',
         'layers/texture_layer_impl.h',
         'layers/tiled_layer.cc',
         'layers/tiled_layer.h',
         'layers/tiled_layer_impl.cc',
         'layers/tiled_layer_impl.h',
         'layers/video_frame_provider.h',
@@ skipping 211 matching lines @@
         'trees/thread_proxy.cc',
         'trees/thread_proxy.h',
         'trees/tree_synchronizer.cc',
         'trees/tree_synchronizer.h',
       ],
       # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
       'msvs_disabled_warnings': [ 4267, ],
     },
   ],
 }