Update a result vector when sampling animation effects.

Source/core/animation/InertAnimation.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 28 matching lines @@
     return adoptRefWillBeNoop(new InertAnimation(effect, timing, paused));
 }
 
 InertAnimation::InertAnimation(PassRefPtrWillBeRawPtr<AnimationEffect> effect, const Timing& timing, bool paused)
     : AnimationNode(timing)
     , m_effect(effect)
     , m_paused(paused)
 {
 }
 
-PassOwnPtrWillBeRawPtr<WillBeHeapVector<RefPtrWillBeMember<Interpolation> > > InertAnimation::sample(double inheritedTime)
+void InertAnimation::sample(double inheritedTime, OwnPtrWillBeRawPtr<WillBeHeapVector<RefPtrWillBeMember<Interpolation>>>& result)
 {
     updateInheritedTime(inheritedTime, TimingUpdateOnDemand);
-    if (!isInEffect())
-        return nullptr;
+    if (!isInEffect()) {
+        result.clear();
+        return;
+    }
 
     double iteration = currentIteration();
     ASSERT(iteration >= 0);
     // FIXME: Handle iteration values which overflow int.
-    return m_effect->sample(static_cast<int>(iteration), timeFraction(), iterationDuration());
+    return m_effect->sample(static_cast<int>(iteration), timeFraction(), iterationDuration(), result);
 }
 
 double InertAnimation::calculateTimeToEffectChange(bool, double, double) const
 {
     return std::numeric_limits<double>::infinity();
 }
 
 void InertAnimation::trace(Visitor* visitor)
 {
     visitor->trace(m_effect);
     AnimationNode::trace(visitor);
 }
 
 } // namespace blink