Use a struct for cc::Surface ids for more type safety

cc/quads/surface_draw_quad.cc

 // 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.
 
 #include "cc/quads/surface_draw_quad.h"
 
 #include "base/logging.h"
 #include "base/values.h"
 
 namespace cc {
 
-SurfaceDrawQuad::SurfaceDrawQuad() : surface_id(0) {}
+SurfaceDrawQuad::SurfaceDrawQuad() {
+}
 
 scoped_ptr<SurfaceDrawQuad> SurfaceDrawQuad::Create() {
   return make_scoped_ptr(new SurfaceDrawQuad);
 }
 
 void SurfaceDrawQuad::SetNew(const SharedQuadState* shared_quad_state,
                              const gfx::Rect& rect,
                              const gfx::Rect& visible_rect,
-                             int surface_id) {
+                             SurfaceId surface_id) {
   gfx::Rect opaque_rect;
   bool needs_blending = false;
   DrawQuad::SetAll(shared_quad_state, DrawQuad::SURFACE_CONTENT, rect,
                    opaque_rect, visible_rect, needs_blending);
   this->surface_id = surface_id;
 }
 
 void SurfaceDrawQuad::SetAll(const SharedQuadState* shared_quad_state,
                              const gfx::Rect& rect,
                              const gfx::Rect& opaque_rect,
                              const gfx::Rect& visible_rect,
                              bool needs_blending,
-                             int surface_id) {
+                             SurfaceId surface_id) {
   DrawQuad::SetAll(shared_quad_state, DrawQuad::SURFACE_CONTENT, rect,
                    opaque_rect, visible_rect, needs_blending);
   this->surface_id = surface_id;
 }
 
 void SurfaceDrawQuad::IterateResources(
     const ResourceIteratorCallback& callback) {}
 
 const SurfaceDrawQuad* SurfaceDrawQuad::MaterialCast(const DrawQuad* quad) {
   DCHECK_EQ(quad->material, DrawQuad::SURFACE_CONTENT);
   return static_cast<const SurfaceDrawQuad*>(quad);
 }
 
 void SurfaceDrawQuad::ExtendValue(base::DictionaryValue* value) const {
-  value->SetInteger("surface_id", surface_id);
+  value->SetInteger("surface_id", surface_id.id);
 }
 
 
 }  // namespace cc