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

cc/surfaces/surface.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/surfaces/surface.h"
 
 #include "cc/output/compositor_frame.h"
 #include "cc/surfaces/surface_manager.h"
 
 namespace cc {
 
 Surface::Surface(SurfaceManager* manager,
                  SurfaceClient* client,
                  const gfx::Size& size)
     : manager_(manager),
       client_(client),
       size_(size) {
-  surface_id_ = manager_->RegisterAndAllocateIDForSurface(this);
+  surface_id_ = manager_->RegisterAndAllocateIdForSurface(this);
 }
 
 Surface::~Surface() {
   manager_->DeregisterSurface(surface_id_);
 }
 
 void Surface::QueueFrame(scoped_ptr<CompositorFrame> frame) {
   current_frame_ = frame.Pass();
 }
 
 CompositorFrame* Surface::GetEligibleFrame() { return current_frame_.get(); }
 
 }  // namespace cc