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

cc/blink/web_transform_animation_curve_impl.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 "cc/blink/web_transform_animation_curve_impl.h"
 
 #include "cc/animation/keyframed_animation_curve.h"
 #include "cc/animation/timing_function.h"
 #include "cc/animation/transform_operations.h"
 #include "cc/blink/web_animation_curve_common.h"
@@ skipping 32 matching lines @@
                                          double x1,
                                          double y1,
                                          double x2,
                                          double y2) {
   const cc::TransformOperations& transform_operations =
       static_cast<const WebTransformOperationsImpl&>(keyframe.value())
           .AsTransformOperations();
   curve_->AddKeyframe(cc::TransformKeyframe::Create(
       keyframe.time(),
       transform_operations,
-      cc::CubicBezierTimingFunction::Create(x1, y1, x2, y2)));
+      cc::CubicBezierTimingFunction::Create(x1, y1, x2, y2)
+          .PassAs<cc::TimingFunction>()));
 }
 
 scoped_ptr<cc::AnimationCurve>
 WebTransformAnimationCurveImpl::CloneToAnimationCurve() const {
   return curve_->Clone();
 }
 
 }  // namespace cc_blink