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

cc/layers/picture_layer_impl.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/layers/picture_layer_impl.h"
 
 #include <algorithm>
 
 #include "base/time.h"
 #include "cc/base/math_util.h"
@@ skipping 75 matching lines @@
   layer_impl->raster_device_scale_ = raster_device_scale_;
   layer_impl->raster_source_scale_ = raster_source_scale_;
   layer_impl->raster_contents_scale_ = raster_contents_scale_;
   layer_impl->low_res_raster_contents_scale_ = low_res_raster_contents_scale_;
   layer_impl->is_using_lcd_text_ = is_using_lcd_text_;
 }
 
 
 void PictureLayerImpl::AppendQuads(QuadSink* quad_sink,
                                    AppendQuadsData* append_quads_data) {
-  const gfx::Rect& rect = visible_content_rect();
+  gfx::Rect rect(visible_content_rect());
   gfx::Rect content_rect(content_bounds());
 
   SharedQuadState* shared_quad_state =
       quad_sink->UseSharedQuadState(CreateSharedQuadState());
   AppendDebugBorderQuad(quad_sink, shared_quad_state, append_quads_data);
 
   bool clipped = false;
   gfx::QuadF target_quad = MathUtil::MapQuad(
       draw_transform(),
       gfx::QuadF(rect),
@@ skipping 426 matching lines @@
       return 0;
     return iter->drawing_info().get_resource_id();
   }
   return 0;
 }
 
 bool PictureLayerImpl::AreVisibleResourcesReady() const {
   DCHECK(layer_tree_impl()->IsPendingTree());
   DCHECK(ideal_contents_scale_);
 
-  const gfx::Rect& rect = visible_content_rect();
+  gfx::Rect rect(visible_content_rect());
 
   float min_acceptable_scale =
       std::min(raster_contents_scale_, ideal_contents_scale_);
 
   TreePriority tree_priority =
       layer_tree_impl()->tile_manager()->GlobalState().tree_priority;
   bool should_force_uploads =
       tree_priority != SMOOTHNESS_TAKES_PRIORITY &&
       layer_tree_impl()->animationRegistrar()->
           active_animation_controllers().empty();
@@ skipping 352 matching lines @@
 scoped_ptr<base::Value> PictureLayerImpl::AsValue() const {
   scoped_ptr<base::DictionaryValue> state(new base::DictionaryValue());
   LayerImpl::AsValueInto(state.get());
 
   state->SetDouble("ideal_contents_scale", ideal_contents_scale_);
   state->Set("tilings", tilings_->AsValue().release());
   return state.PassAs<base::Value>();
 }
 
 }  // namespace cc