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

cc/resources/bitmap_content_layer_updater.cc

 // Copyright 2011 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/bitmap_content_layer_updater.h"
 
 #include "cc/debug/devtools_instrumentation.h"
 #include "cc/debug/rendering_stats_instrumentation.h"
 #include "cc/resources/layer_painter.h"
 #include "cc/resources/prioritized_resource.h"
 #include "cc/resources/resource_update.h"
 #include "cc/resources/resource_update_queue.h"
 #include "skia/ext/platform_canvas.h"
 
 namespace cc {
 
 BitmapContentLayerUpdater::Resource::Resource(
     BitmapContentLayerUpdater* updater,
     scoped_ptr<PrioritizedResource> texture)
     : LayerUpdater::Resource(texture.Pass()), updater_(updater) {}
 
 BitmapContentLayerUpdater::Resource::~Resource() {}
 
-void BitmapContentLayerUpdater::Resource::Update(ResourceUpdateQueue* queue,
-                                                 const gfx::Rect& source_rect,
-                                                 gfx::Vector2d dest_offset,
-                                                 bool partial_update) {
+void BitmapContentLayerUpdater::Resource::Update(
+    ResourceUpdateQueue* queue,
+    const gfx::Rect& source_rect,
+    const gfx::Vector2d& dest_offset,
+    bool partial_update) {
   updater_->UpdateTexture(
       queue, texture(), source_rect, dest_offset, partial_update);
 }
 
 scoped_refptr<BitmapContentLayerUpdater> BitmapContentLayerUpdater::Create(
     scoped_ptr<LayerPainter> painter,
     RenderingStatsInstrumentation* stats_instrumentation,
     int layer_id) {
   return make_scoped_refptr(
       new BitmapContentLayerUpdater(painter.Pass(),
@@ skipping 43 matching lines @@
   base::TimeDelta duration =
       rendering_stats_instrumentation_->EndRecording(start_time);
   rendering_stats_instrumentation_->AddPaint(
       duration,
       content_rect.width() * content_rect.height());
 }
 
 void BitmapContentLayerUpdater::UpdateTexture(ResourceUpdateQueue* queue,
                                               PrioritizedResource* texture,
                                               const gfx::Rect& source_rect,
-                                              gfx::Vector2d dest_offset,
+                                              const gfx::Vector2d& dest_offset,
                                               bool partial_update) {
   CHECK(canvas_);
   ResourceUpdate upload = ResourceUpdate::Create(texture,
                                                  &bitmap_backing_,
                                                  content_rect(),
                                                  source_rect,
                                                  dest_offset);
   if (partial_update)
     queue->AppendPartialUpload(upload);
   else
     queue->AppendFullUpload(upload);
 }
 
 void BitmapContentLayerUpdater::ReduceMemoryUsage() {
   canvas_.clear();
   canvas_size_ = gfx::Size();
 }
 
 void BitmapContentLayerUpdater::SetOpaque(bool opaque) {
   if (opaque != layer_is_opaque_) {
     canvas_.clear();
     canvas_size_ = gfx::Size();
   }
 
   ContentLayerUpdater::SetOpaque(opaque);
 }
 
 }  // namespace cc