cc: Use const ref to avoid extra ref count of VideoProviderClientImpl.

cc/layers/video_layer_impl.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/layers/video_layer_impl.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "cc/layers/video_frame_provider_client_impl.h"
 #include "cc/quads/io_surface_draw_quad.h"
@@ skipping 25 matching lines @@
   scoped_refptr<VideoFrameProviderClientImpl> provider_client_impl =
       VideoFrameProviderClientImpl::Create(provider);
 
   return make_scoped_ptr(
       new VideoLayerImpl(tree_impl, id, provider_client_impl, video_rotation));
 }
 
 VideoLayerImpl::VideoLayerImpl(
     LayerTreeImpl* tree_impl,
     int id,
-    scoped_refptr<VideoFrameProviderClientImpl> provider_client_impl,
+    const scoped_refptr<VideoFrameProviderClientImpl>& provider_client_impl,
     media::VideoRotation video_rotation)
     : LayerImpl(tree_impl, id),
       provider_client_impl_(provider_client_impl),
       frame_(nullptr),
       video_rotation_(video_rotation) {
 }
 
 VideoLayerImpl::~VideoLayerImpl() {
   if (!provider_client_impl_->Stopped()) {
     // In impl side painting, we may have a pending and active layer
@@ skipping 313 matching lines @@
 void VideoLayerImpl::SetNeedsRedraw() {
   SetUpdateRect(gfx::UnionRects(update_rect(), gfx::Rect(bounds())));
   layer_tree_impl()->SetNeedsRedraw();
 }
 
 const char* VideoLayerImpl::LayerTypeAsString() const {
   return "cc::VideoLayerImpl";
 }
 
 }  // namespace cc