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

cc/trees/single_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/single_thread_proxy.h"
 
 #include "base/auto_reset.h"
 #include "base/debug/trace_event.h"
 #include "cc/debug/benchmark_instrumentation.h"
 #include "cc/output/context_provider.h"
 #include "cc/output/output_surface.h"
 #include "cc/quads/draw_quad.h"
 #include "cc/resources/prioritized_resource_manager.h"
 #include "cc/resources/resource_update_controller.h"
 #include "cc/trees/blocking_task_runner.h"
 #include "cc/trees/layer_tree_host.h"
 #include "cc/trees/layer_tree_host_single_thread_client.h"
 #include "cc/trees/layer_tree_impl.h"
 #include "cc/trees/scoped_abort_remaining_swap_promises.h"
 #include "ui/gfx/frame_time.h"
 
 namespace cc {
 
 scoped_ptr<Proxy> SingleThreadProxy::Create(
     LayerTreeHost* layer_tree_host,
     LayerTreeHostSingleThreadClient* client,
     scoped_refptr<base::SingleThreadTaskRunner> main_task_runner) {
   return make_scoped_ptr(
-      new SingleThreadProxy(layer_tree_host, client, main_task_runner));
+             new SingleThreadProxy(layer_tree_host, client, main_task_runner))
+      .PassAs<Proxy>();
 }
 
 SingleThreadProxy::SingleThreadProxy(
     LayerTreeHost* layer_tree_host,
     LayerTreeHostSingleThreadClient* client,
     scoped_refptr<base::SingleThreadTaskRunner> main_task_runner)
     : Proxy(main_task_runner, NULL),
       layer_tree_host_(layer_tree_host),
       client_(client),
       timing_history_(layer_tree_host->rendering_stats_instrumentation()),
@@ skipping 266 matching lines @@
   TRACE_EVENT0("cc", "SingleThreadProxy::stop");
   DCHECK(Proxy::IsMainThread());
   {
     DebugScopedSetMainThreadBlocked main_thread_blocked(this);
     DebugScopedSetImplThread impl(this);
 
     BlockingTaskRunner::CapturePostTasks blocked(
         blocking_main_thread_task_runner());
     layer_tree_host_->DeleteContentsTexturesOnImplThread(
         layer_tree_host_impl_->resource_provider());
-    scheduler_on_impl_thread_ = nullptr;
-    layer_tree_host_impl_ = nullptr;
+    scheduler_on_impl_thread_.reset();
+    layer_tree_host_impl_.reset();
   }
   layer_tree_host_ = NULL;
 }
 
 void SingleThreadProxy::OnCanDrawStateChanged(bool can_draw) {
   TRACE_EVENT1(
       "cc", "SingleThreadProxy::OnCanDrawStateChanged", "can_draw", can_draw);
   DCHECK(Proxy::IsImplThread());
   UpdateBackgroundAnimateTicking();
   if (scheduler_on_impl_thread_)
@@ skipping 361 matching lines @@
 
 base::TimeDelta SingleThreadProxy::CommitToActivateDurationEstimate() {
   return timing_history_.CommitToActivateDurationEstimate();
 }
 
 void SingleThreadProxy::DidBeginImplFrameDeadline() {
   layer_tree_host_impl_->ResetCurrentBeginFrameArgsForNextFrame();
 }
 
 }  // namespace cc