cc: Remove use of PassAs() and constructor-casting with scoped_ptr.

cc/layers/layer.cc

 // Copyright 2010 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/layer.h"
 
 #include <algorithm>
 
 #include "base/atomic_sequence_num.h"
 #include "base/debug/trace_event.h"
@@ skipping 602 matching lines @@
 void Layer::AddScrollChild(Layer* child) {
   if (!scroll_children_)
     scroll_children_.reset(new std::set<Layer*>);
   scroll_children_->insert(child);
   SetNeedsCommit();
 }
 
 void Layer::RemoveScrollChild(Layer* child) {
   scroll_children_->erase(child);
   if (scroll_children_->empty())
-    scroll_children_.reset();
+    scroll_children_ = nullptr;
   SetNeedsCommit();
 }
 
 void Layer::SetClipParent(Layer* ancestor) {
   DCHECK(IsPropertyChangeAllowed());
   if (clip_parent_ == ancestor)
     return;
 
   if (clip_parent_)
     clip_parent_->RemoveClipChild(this);
 
   clip_parent_ = ancestor;
 
   if (clip_parent_)
     clip_parent_->AddClipChild(this);
 
   SetNeedsCommit();
 }
 
 void Layer::AddClipChild(Layer* child) {
   if (!clip_children_)
     clip_children_.reset(new std::set<Layer*>);
   clip_children_->insert(child);
   SetNeedsCommit();
 }
 
 void Layer::RemoveClipChild(Layer* child) {
   clip_children_->erase(child);
   if (clip_children_->empty())
-    clip_children_.reset();
+    clip_children_ = nullptr;
   SetNeedsCommit();
 }
 
 void Layer::SetScrollOffset(gfx::Vector2d scroll_offset) {
   DCHECK(IsPropertyChangeAllowed());
 
   if (scroll_offset_ == scroll_offset)
     return;
   scroll_offset_ = scroll_offset;
   SetNeedsCommit();
@@ skipping 414 matching lines @@
     return NULL;
 }
 
 void Layer::CreateRenderSurface() {
   DCHECK(!draw_properties_.render_surface);
   draw_properties_.render_surface = make_scoped_ptr(new RenderSurface(this));
   draw_properties_.render_target = this;
 }
 
 void Layer::ClearRenderSurface() {
-  draw_properties_.render_surface.reset();
+  draw_properties_.render_surface = nullptr;
 }
 
 void Layer::ClearRenderSurfaceLayerList() {
   if (draw_properties_.render_surface)
     draw_properties_.render_surface->layer_list().clear();
 }
 
 gfx::Vector2dF Layer::ScrollOffsetForAnimation() const {
   return TotalScrollOffset();
 }
@@ skipping 134 matching lines @@
 
 void Layer::RunMicroBenchmark(MicroBenchmark* benchmark) {
   benchmark->RunOnLayer(this);
 }
 
 bool Layer::HasDelegatedContent() const {
   return false;
 }
 
 }  // namespace cc