Enable accelerated animations for orphaned layers

cc/layer_impl.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/layer_impl.h"
 
 #include "base/debug/trace_event.h"
 #include "base/stringprintf.h"
 #include "base/values.h"
 #include "cc/animation_registrar.h"
@@ skipping 487 matching lines @@
 void LayerImpl::OnTransformAnimated(const gfx::Transform& transform)
 {
     setTransform(transform);
 }
 
 bool LayerImpl::IsActive() const
 {
     return m_layerTreeImpl->IsActiveTree();
 }
 
+bool LayerImpl::IsOrphaned() const
+{
+    return false;
+}
+
 void LayerImpl::setBounds(const gfx::Size& bounds)
 {
     if (m_bounds == bounds)
         return;
 
     m_bounds = bounds;
 
     if (masksToBounds())
         noteLayerPropertyChangedForSubtree();
     else
@@ skipping 345 matching lines @@
     if (!m_scrollbarAnimationController) {
         if (m_layerTreeImpl->settings().useLinearFadeScrollbarAnimator)
             m_scrollbarAnimationController = createScrollbarAnimationControllerWithFade(this);
         else
             m_scrollbarAnimationController = ScrollbarAnimationController::create(this);
     }
     m_scrollbarAnimationController->setVerticalScrollbarLayer(scrollbarLayer);
 }
 
 }  // namespace cc