[#2] Pass gfx structs by const ref (gfx::Rect, gfx::RectF)

cc/test/test_context_support.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 "cc/test/test_context_support.h"
 
 #include "base/bind.h"
 #include "base/message_loop/message_loop.h"
 
 namespace cc {
@@ skipping 45 matching lines @@
   set_visible_callback_ = set_visible_callback;
 }
 
 void TestContextSupport::Swap() {
   last_swap_type_ = SWAP;
   base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(&TestContextSupport::OnSwapBuffersComplete,
                             weak_ptr_factory_.GetWeakPtr()));
 }
 
-void TestContextSupport::PartialSwapBuffers(gfx::Rect sub_buffer) {
+void TestContextSupport::PartialSwapBuffers(const gfx::Rect& sub_buffer) {
   last_swap_type_ = PARTIAL_SWAP;
   last_partial_swap_rect_ = sub_buffer;
   base::MessageLoop::current()->PostTask(
       FROM_HERE, base::Bind(&TestContextSupport::OnSwapBuffersComplete,
                             weak_ptr_factory_.GetWeakPtr()));
 }
 
 void TestContextSupport::SetSwapBuffersCompleteCallback(
     const base::Closure& callback) {
   swap_buffers_complete_callback_ = callback;
 }
 
 void TestContextSupport::OnSwapBuffersComplete() {
   if (!swap_buffers_complete_callback_.is_null())
     swap_buffers_complete_callback_.Run();
 }
 
 }  // namespace cc