blink: Add backdrop-filter support

Source/core/animation/css/CSSAnimations.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 324 matching lines @@
                 toDeferredLegacyStyleInterpolation(toStyleInterpolation(interpolation)).underlyingStyleChanged();
         });
 
         bool updated = false;
         if (styleUpdate.snapshot.opacity)
             updated |= styleUpdate.model->updateNeutralKeyframeAnimatableValues(CSSPropertyOpacity, styleUpdate.snapshot.opacity);
         if (styleUpdate.snapshot.transform)
             updated |= styleUpdate.model->updateNeutralKeyframeAnimatableValues(CSSPropertyTransform, styleUpdate.snapshot.transform);
         if (styleUpdate.snapshot.webkitFilter)
             updated |= styleUpdate.model->updateNeutralKeyframeAnimatableValues(CSSPropertyWebkitFilter, styleUpdate.snapshot.webkitFilter);
+        if (styleUpdate.snapshot.backdropFilter)
+            updated |= styleUpdate.model->updateNeutralKeyframeAnimatableValues(CSSPropertyBackdropFilter, styleUpdate.snapshot.backdropFilter);
         if (updated) {
             styleUpdate.animation->setOutdated();
             styleUpdate.animation->setCompositorPending(true);
         }
     }
 
     for (const auto& entry : update->animationsWithUpdates()) {
         KeyframeEffect* effect = toKeyframeEffect(entry.animation->effect());
 
         effect->setModel(entry.effect->model());
@@ skipping 452 matching lines @@
     visitor->trace(m_activeInterpolationsForAnimations);
     visitor->trace(m_activeInterpolationsForTransitions);
     visitor->trace(m_newAnimations);
     visitor->trace(m_suppressedAnimations);
     visitor->trace(m_animationsWithUpdates);
     visitor->trace(m_animationsWithStyleUpdates);
 #endif
 }
 
 } // namespace blink