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

cc/trees/layer_tree_host_unittest_no_message_loop.cc

 // Copyright 2014 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 "base/message_loop/message_loop_proxy.h"
 #include "base/threading/simple_thread.h"
 #include "cc/layers/delegated_frame_provider.h"
 #include "cc/layers/delegated_frame_resource_collection.h"
 #include "cc/layers/delegated_renderer_layer.h"
 #include "cc/layers/layer.h"
@@ skipping 95 matching lines @@
     did_commit_ = false;
     did_commit_and_draw_frame_ = false;
     layer_tree_host_->Composite(gfx::FrameTime::Now());
     EXPECT_TRUE(did_initialize_output_surface_);
     EXPECT_TRUE(did_commit_);
     EXPECT_TRUE(did_commit_and_draw_frame_);
   }
 
   void TearDownLayerTreeHost() {
     // Explicit teardown to make failures easier to debug.
-    layer_tree_host_.reset();
-    root_layer_ = NULL;
+    layer_tree_host_ = nullptr;
+    root_layer_ = nullptr;
   }
 
   // All protected member variables are accessed only on |no_loop_thread_|.
   scoped_ptr<LayerTreeHost> layer_tree_host_;
   scoped_refptr<Layer> root_layer_;
 
   bool did_initialize_output_surface_;
   bool did_commit_;
   bool did_commit_and_draw_frame_;
   gfx::Size size_;
@@ skipping 99 matching lines @@
   scoped_refptr<DelegatedFrameProvider> frame_provider_;
   scoped_refptr<DelegatedRendererLayer> delegated_layer_;
 };
 
 TEST_F(LayerTreeHostNoMessageLoopDelegatedLayer, SingleDelegatedLayer) {
   RunTest();
 }
 
 }  // namespace
 }  // namespace cc