Add Protobuf support for cc/playback skia usage

cc/BUILD.gn

 # Copyright 2014 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.
 
 import("//testing/test.gni")
 
 component("cc") {
   sources = [
     "animation/animation.cc",
     "animation/animation.h",
@@ skipping 296 matching lines @@
     "playback/float_clip_display_item.h",
     "playback/largest_display_item.cc",
     "playback/largest_display_item.h",
     "playback/raster_source.h",
     "playback/raster_source_helper.cc",
     "playback/raster_source_helper.h",
     "playback/transform_display_item.cc",
     "playback/transform_display_item.h",
     "proto/gfx_conversions.cc",
     "proto/gfx_conversions.h",
+    "proto/skia_conversions.cc",
+    "proto/skia_conversions.h",
     "quads/content_draw_quad_base.cc",
     "quads/content_draw_quad_base.h",
     "quads/debug_border_draw_quad.cc",
     "quads/debug_border_draw_quad.h",
     "quads/draw_polygon.cc",
     "quads/draw_polygon.h",
     "quads/draw_quad.cc",
     "quads/draw_quad.h",
     "quads/io_surface_draw_quad.cc",
     "quads/io_surface_draw_quad.h",
@@ skipping 450 matching lines @@
     "output/renderer_pixeltest.cc",
     "output/renderer_unittest.cc",
     "output/shader_unittest.cc",
     "output/software_renderer_unittest.cc",
     "output/texture_mailbox_deleter_unittest.cc",
     "playback/discardable_image_map_unittest.cc",
     "playback/display_item_list_unittest.cc",
     "playback/display_list_raster_source_unittest.cc",
     "playback/display_list_recording_source_unittest.cc",
     "proto/gfx_conversions_unittest.cc",
+    "proto/skia_conversions_unittest.cc",
     "quads/draw_polygon_unittest.cc",
     "quads/draw_quad_unittest.cc",
     "quads/render_pass_unittest.cc",
     "raster/scoped_gpu_raster_unittest.cc",
     "raster/task_graph_runner_unittest.cc",
     "raster/texture_compressor_etc1_unittest.cc",
     "raster/tile_task_worker_pool_unittest.cc",
     "resources/platform_color_unittest.cc",
     "resources/resource_pool_unittest.cc",
     "resources/resource_provider_unittest.cc",
@@ skipping 127 matching lines @@
     "//ui/gl",
     "//ui/gl:test_support",
   ]
 
   if (is_android) {
     isolate_file = "cc_perftests.isolate"
   }
 }
 # When adding support for isolates, please have a look at run-time dependencies
 # in the cc_unittests_run target in cc_tests.gyp.