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

cc/resources/prioritized_resource_manager.h

Index: cc/resources/prioritized_resource_manager.h
diff --git a/cc/resources/prioritized_resource_manager.h b/cc/resources/prioritized_resource_manager.h
index 092b1d720fd7e1479ca6e5af2455d267da9b52a1..9b558a45b8ffa3a660d885a17c07da7348e49cb3 100644
--- a/cc/resources/prioritized_resource_manager.h
+++ b/cc/resources/prioritized_resource_manager.h
@@ -40,7 +40,7 @@
     return make_scoped_ptr(new PrioritizedResourceManager(proxy));
   }
   scoped_ptr<PrioritizedResource> CreateTexture(
-      const gfx::Size& size, ResourceFormat format) {
+      gfx::Size size, ResourceFormat format) {
     return make_scoped_ptr(new PrioritizedResource(this, size, format));
   }
   ~PrioritizedResourceManager();
@@ -189,7 +189,7 @@
                                    UnlinkPolicy unlink_policy,
                                    ResourceProvider* resource_provider);
   PrioritizedResource::Backing* CreateBacking(
-      const gfx::Size& size,
+      gfx::Size size,
       ResourceFormat format,
       ResourceProvider* resource_provider);
   void EvictFirstBackingResource(ResourceProvider* resource_provider);