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

cc/layers/solid_color_scrollbar_layer.cc

 // Copyright 2013 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/solid_color_scrollbar_layer.h"
 
 #include "base/memory/scoped_ptr.h"
 #include "cc/layers/layer_impl.h"
 #include "cc/layers/solid_color_scrollbar_layer_impl.h"
 
 namespace cc {
 
 scoped_ptr<LayerImpl> SolidColorScrollbarLayer::CreateLayerImpl(
     LayerTreeImpl* tree_impl) {
   const bool kIsOverlayScrollbar = true;
   return SolidColorScrollbarLayerImpl::Create(tree_impl,
                                               id(),
                                               orientation(),
                                               thumb_thickness_,
                                               track_start_,
                                               is_left_side_vertical_scrollbar_,
-                                              kIsOverlayScrollbar);
+                                              kIsOverlayScrollbar)
+      .PassAs<LayerImpl>();
 }
 
 scoped_refptr<SolidColorScrollbarLayer> SolidColorScrollbarLayer::Create(
     ScrollbarOrientation orientation,
     int thumb_thickness,
     int track_start,
     bool is_left_side_vertical_scrollbar,
     int scroll_layer_id) {
   return make_scoped_refptr(
       new SolidColorScrollbarLayer(orientation,
@@ skipping 61 matching lines @@
 
   clip_layer_id_ = layer_id;
   SetNeedsFullTreeSync();
 }
 
 ScrollbarOrientation SolidColorScrollbarLayer::orientation() const {
   return orientation_;
 }
 
 }  // namespace cc