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

cc/input/top_controls_manager.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/input/top_controls_manager.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "cc/animation/keyframed_animation_curve.h"
@@ skipping 162 matching lines @@
   SetControlsTopOffset(top_controls_animation_->GetValue(time));
 
   if (IsAnimationCompleteAtTime(monotonic_time))
     ResetAnimations();
 
   gfx::Vector2dF scroll_delta(0.f, client_->ControlsTopOffset() - old_offset);
   return scroll_delta;
 }
 
 void TopControlsManager::ResetAnimations() {
-  top_controls_animation_ = nullptr;
+  if (top_controls_animation_)
+    top_controls_animation_.reset();
+
   animation_direction_ = NO_ANIMATION;
 }
 
 void TopControlsManager::SetupAnimation(AnimationDirection direction) {
   DCHECK(direction != NO_ANIMATION);
 
   if (direction == SHOWING_CONTROLS && client_->ControlsTopOffset() == 0)
     return;
 
   if (direction == HIDING_CONTROLS &&
@@ skipping 53 matching lines @@
 
   if ((animation_direction_ == SHOWING_CONTROLS && new_offset >= 0) ||
       (animation_direction_ == HIDING_CONTROLS
           && new_offset <= -top_controls_height_)) {
     return true;
   }
   return false;
 }
 
 }  // namespace cc