[#6]Pass gfx structs by const ref (gfx::Vector2d)

cc/resources/prioritized_resource.cc

 // Copyright 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.
 
 #include "cc/resources/prioritized_resource.h"
 
 #include <algorithm>
 
 #include "cc/resources/platform_color.h"
 #include "cc/resources/prioritized_resource_manager.h"
@@ skipping 61 matching lines @@
     ResourceProvider* resource_provider) {
   DCHECK(is_above_priority_cutoff_);
   if (is_above_priority_cutoff_)
     manager_->AcquireBackingTextureIfNeeded(this, resource_provider);
 }
 
 void PrioritizedResource::SetPixels(ResourceProvider* resource_provider,
                                     const uint8_t* image,
                                     const gfx::Rect& image_rect,
                                     const gfx::Rect& source_rect,
-                                    gfx::Vector2d dest_offset) {
+                                    const gfx::Vector2d& dest_offset) {
   DCHECK(is_above_priority_cutoff_);
   if (is_above_priority_cutoff_)
     AcquireBackingTexture(resource_provider);
   DCHECK(backing_);
   resource_provider->SetPixels(
       resource_id(), image, image_rect, source_rect, dest_offset);
 
   // The component order may be bgra if we uploaded bgra pixels to rgba
   // texture. Mark contents as swizzled if image component order is
   // different than texture format.
@@ skipping 100 matching lines @@
     manager_->ReturnBackingTexture(this);
 }
 
 const Proxy* PrioritizedResource::Backing::proxy() const {
   if (!owner_ || !owner_->resource_manager())
     return NULL;
   return owner_->resource_manager()->ProxyForDebug();
 }
 
 }  // namespace cc