Add machinery for dumping SkPictures to disk

sky/shell/BUILD.gn

 # Copyright 2015 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.
 
 common_deps = [
   "//base",
   "//base:i18n",
   "//build/config/sanitizers:deps",
   "//dart/runtime:libdart",
   "//mojo/common",
@@ skipping 14 matching lines @@
   "//ui/gfx/geometry",
   "//ui/gl",
 ]
 
 source_set("common") {
   sources = [
     "gpu/ganesh_context.cc",
     "gpu/ganesh_context.h",
     "gpu/ganesh_surface.cc",
     "gpu/ganesh_surface.h",
+    "gpu/picture_serializer.cc",
+    "gpu/picture_serializer.h",
     "gpu/rasterizer.cc",
     "gpu/rasterizer.h",
     "gpu_delegate.cc",
     "gpu_delegate.h",
     "platform_view.cc",
     "platform_view.h",
     "service_provider.cc",
     "service_provider.h",
     "shell.cc",
     "shell.h",
@@ skipping 145 matching lines @@
     ]
 
     deps = common_deps + [
              ":common",
              "//sky/services/testing:interfaces",
            ]
   }
 } else {
   assert(false, "Unsupported platform")
 }