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

content/test/web_layer_tree_view_impl_for_testing.cc

 // Copyright 2013 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 "content/test/web_layer_tree_view_impl_for_testing.h"
 
 #include "base/command_line.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/synchronization/lock.h"
 #include "cc/base/switches.h"
@@ skipping 130 matching lines @@
 void WebLayerTreeViewImplForTesting::setDeferCommits(bool defer_commits) {
   layer_tree_host_->SetDeferCommits(defer_commits);
 }
 
 void WebLayerTreeViewImplForTesting::renderingStats(WebRenderingStats&) const {}
 
 void WebLayerTreeViewImplForTesting::Layout() {
 }
 
 void WebLayerTreeViewImplForTesting::ApplyScrollAndScale(
-    gfx::Vector2d scroll_delta,
+    const gfx::Vector2d& scroll_delta,
     float page_scale) {}
 
 scoped_ptr<cc::OutputSurface>
 WebLayerTreeViewImplForTesting::CreateOutputSurface(bool fallback) {
   return make_scoped_ptr(
       new cc::OutputSurface(cc::TestContextProvider::Create()));
 }
 
 scoped_refptr<cc::ContextProvider>
 WebLayerTreeViewImplForTesting::OffscreenContextProvider() {
   // Unit tests only run in single threaded mode.
   return webkit::gpu::TestContextProviderFactory::GetInstance()->
       OffscreenContextProviderForMainThread();
 }
 
 }  // namespace webkit