Revert of [#7] Pass gfx structs by const ref (gfx::Size)

cc/resources/prioritized_resource_manager.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_manager.h"
 
 #include <algorithm>
 
 #include "base/debug/trace_event.h"
 #include "base/stl_util.h"
@@ skipping 427 matching lines @@
 
 void PrioritizedResourceManager::ReturnBackingTexture(
     PrioritizedResource* texture) {
   DCHECK(proxy_->IsMainThread() ||
          (proxy_->IsImplThread() && proxy_->IsMainThreadBlocked()));
   if (texture->backing())
     texture->Unlink();
 }
 
 PrioritizedResource::Backing* PrioritizedResourceManager::CreateBacking(
-    const gfx::Size& size,
+    gfx::Size size,
     ResourceFormat format,
     ResourceProvider* resource_provider) {
   DCHECK(proxy_->IsImplThread() && proxy_->IsMainThreadBlocked());
   DCHECK(resource_provider);
   ResourceProvider::ResourceId resource_id =
       resource_provider->CreateManagedResource(
           size,
           GL_TEXTURE_2D,
           GL_CLAMP_TO_EDGE,
           ResourceProvider::TextureUsageAny,
@@ skipping 83 matching lines @@
     previous_backing = backing;
   }
 #endif
 }
 
 const Proxy* PrioritizedResourceManager::ProxyForDebug() const {
   return proxy_;
 }
 
 }  // namespace cc