Use StringKeyframes to make CSS Animations responsive to style changes

Source/core/animation/KeyframeEffectModel.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 66 matching lines @@
 {
     ensureKeyframeGroups();
     for (CSSPropertyID property : CompositorAnimations::CompositableProperties) {
         if (!affects(property))
             continue;
         for (auto& keyframe : m_keyframeGroups->get(property)->m_keyframes)
             keyframe->ensureAnimatableValue(property, element, baseStyle);
     }
 }
 
-void KeyframeEffectModelBase::updateNeutralKeyframeAnimatableValues(CSSPropertyID property, PassRefPtrWillBeRawPtr<AnimatableValue> value)
+bool KeyframeEffectModelBase::updateNeutralKeyframeAnimatableValues(CSSPropertyID property, PassRefPtrWillBeRawPtr<AnimatableValue> value)
 {
     ASSERT(CompositorAnimations::isCompositableProperty(property));
 
     if (!value)
-        return;
+        return false;
 
     ensureKeyframeGroups();
     auto& keyframes = m_keyframeGroups->get(property)->m_keyframes;
     ASSERT(keyframes.size() >= 2);
 
     auto& first = toStringPropertySpecificKeyframe(*keyframes.first());
     auto& last = toStringPropertySpecificKeyframe(*keyframes.last());
-    ASSERT(!first.value() || !last.value());
 
     if (!first.value())
         first.setAnimatableValue(value);
     if (!last.value())
         last.setAnimatableValue(value);
+    return !first.value() || !last.value();
 }
 
 KeyframeEffectModelBase::KeyframeVector KeyframeEffectModelBase::normalizedKeyframes(const KeyframeVector& keyframes)
 {
     double lastOffset = 0;
     KeyframeVector result;
     result.reserveCapacity(keyframes.size());
 
     for (const auto& keyframe : keyframes) {
         double offset = keyframe->offset();
@@ skipping 153 matching lines @@
 }
 
 DEFINE_TRACE(KeyframeEffectModelBase::PropertySpecificKeyframeGroup)
 {
 #if ENABLE(OILPAN)
     visitor->trace(m_keyframes);
 #endif
 }
 
 } // namespace