cc: Don't pass simple well-defined classes by reference.

cc/trees/thread_proxy.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/trees/thread_proxy.h"
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
 #include "cc/base/thread.h"
@@ skipping 437 matching lines @@
 
   layer_tree_host_impl_->SendManagedMemoryStats(
       layer_tree_host_->contents_texture_manager()->MemoryVisibleBytes(),
       layer_tree_host_->contents_texture_manager()->
           MemoryVisibleAndNearbyBytes(),
       layer_tree_host_->contents_texture_manager()->MemoryUseBytes());
 }
 
 bool ThreadProxy::IsInsideDraw() { return inside_draw_; }
 
-void ThreadProxy::SetNeedsRedraw(const gfx::Rect& damage_rect) {
+void ThreadProxy::SetNeedsRedraw(gfx::Rect damage_rect) {
   DCHECK(IsMainThread());
   TRACE_EVENT0("cc", "ThreadProxy::SetNeedsRedraw");
   Proxy::ImplThread()->PostTask(base::Bind(
       &ThreadProxy::SetViewportDamageOnImplThread,
       impl_thread_weak_ptr_, damage_rect));
   Proxy::ImplThread()->PostTask(base::Bind(
       &ThreadProxy::SetNeedsRedrawOnImplThread, impl_thread_weak_ptr_));
 }
 
 void ThreadProxy::SetDeferCommits(bool defer_commits) {
@@ skipping 686 matching lines @@
       layer_tree_host_impl_->resource_provider());
   layer_tree_host_impl_->EnableVSyncNotification(false);
   input_handler_on_impl_thread_.reset();
   layer_tree_host_impl_.reset();
   scheduler_on_impl_thread_.reset();
   weak_factory_on_impl_thread_.InvalidateWeakPtrs();
   vsync_client_ = NULL;
   completion->Signal();
 }
 
-void ThreadProxy::SetViewportDamageOnImplThread(const gfx::Rect& damage_rect) {
+void ThreadProxy::SetViewportDamageOnImplThread(gfx::Rect damage_rect) {
   DCHECK(IsImplThread());
   layer_tree_host_impl_->SetViewportDamage(damage_rect);
 }
 
 size_t ThreadProxy::MaxPartialTextureUpdates() const {
   return ResourceUpdateController::MaxPartialTextureUpdates();
 }
 
 void ThreadProxy::RecreateOutputSurfaceOnImplThread(
     CompletionEvent* completion,
@@ skipping 173 matching lines @@
 
 void ThreadProxy::DidReceiveLastInputEventForVSync(
     base::TimeTicks frame_time) {
   if (render_vsync_notification_enabled_) {
     TRACE_EVENT0("cc", "ThreadProxy::DidReceiveLastInputEventForVSync");
     DidVSync(frame_time);
   }
 }
 
 }  // namespace cc