Use StringKeyframes to make CSS Animations responsive to style changes

Source/core/animation/DeferredLegacyStyleInterpolation.cpp

 // 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 "config.h"
 #include "core/animation/DeferredLegacyStyleInterpolation.h"
 
 #include "core/animation/ElementAnimations.h"
 #include "core/animation/css/CSSAnimatableValueFactory.h"
 #include "core/css/CSSImageValue.h"
 #include "core/css/CSSPrimitiveValue.h"
 #include "core/css/CSSSVGDocumentValue.h"
 #include "core/css/CSSShadowValue.h"
 #include "core/css/CSSValueList.h"
 #include "core/css/Pair.h"
 #include "core/css/Rect.h"
 #include "core/css/resolver/StyleResolver.h"
 #include "core/css/resolver/StyleResolverState.h"
 
 namespace blink {
 
 void DeferredLegacyStyleInterpolation::apply(StyleResolverState& state) const
 {
     if (m_outdated || !state.element()->elementAnimations() || !state.element()->elementAnimations()->isAnimationStyleChange()) {
-        m_innerInterpolation = LegacyStyleInterpolation::create(
-            StyleResolver::createAnimatableValueSnapshot(state, m_id, m_startCSSValue.get()),
-            StyleResolver::createAnimatableValueSnapshot(state, m_id, m_endCSSValue.get()),
-            m_id);
+        RefPtrWillBeRawPtr<AnimatableValue> startAnimatableValue;
+        RefPtrWillBeRawPtr<AnimatableValue> endAnimatableValue;
+
+        // Snapshot neutral values first because non-neutral values will mutate the StyleResolverState.

[Timothy Loh, 2015/03/16 00:49:41]

Snapshot underlying values?

[alancutter (OOO until 2018), 2015/03/17 00:12:34]

Done.

+        if (!m_endCSSValue) {
+            endAnimatableValue = StyleResolver::createAnimatableValueSnapshot(state, m_id, m_endCSSValue.get());
+            startAnimatableValue = StyleResolver::createAnimatableValueSnapshot(state, m_id, m_startCSSValue.get());
+        } else {
+            startAnimatableValue = StyleResolver::createAnimatableValueSnapshot(state, m_id, m_startCSSValue.get());
+            endAnimatableValue = StyleResolver::createAnimatableValueSnapshot(state, m_id, m_endCSSValue.get());
+        }
+
+        m_innerInterpolation = LegacyStyleInterpolation::create(startAnimatableValue, endAnimatableValue, m_id);
         m_outdated = false;
     }
 
     m_innerInterpolation->interpolate(m_cachedIteration, m_cachedFraction);
     m_innerInterpolation->apply(state);
 }
 
 bool DeferredLegacyStyleInterpolation::interpolationRequiresStyleResolve(const CSSValue& value)
 {
     // FIXME: should not require resolving styles for initial.
@@ skipping 102 matching lines @@
 
 DEFINE_TRACE(DeferredLegacyStyleInterpolation)
 {
     visitor->trace(m_startCSSValue);
     visitor->trace(m_endCSSValue);
     visitor->trace(m_innerInterpolation);
     StyleInterpolation::trace(visitor);
 }
 
 }