Add CSS property priority for CSS animation affecting properties

third_party/WebKit/Source/core/animation/css/CSSAnimations.cpp

Index: third_party/WebKit/Source/core/animation/css/CSSAnimations.cpp
diff --git a/third_party/WebKit/Source/core/animation/css/CSSAnimations.cpp b/third_party/WebKit/Source/core/animation/css/CSSAnimations.cpp
index 03392eb874d8bb9dc5ca8eff13759b1e3af8d8fc..6728de8b0b262a4aac054086561869958ab5eea6 100644
--- a/third_party/WebKit/Source/core/animation/css/CSSAnimations.cpp
+++ b/third_party/WebKit/Source/core/animation/css/CSSAnimations.cpp
@@ -844,6 +844,13 @@ void CSSAnimations::cancel() {
   clearPendingUpdate();
 }
 
+// TODO(alancutter): CSS properties and presentation attributes may have
+// identical effects. By grouping them in the same set we introduce a bug where
+// arbitrary hash iteration will determine the order the apply in and thus which
+// one "wins". We should be more deliberate about the order of application in
+// the case of effect collisions.
+// Example: Both 'color' and 'svg-color' set the color on ComputedStyle but are
+// considered distinct properties in the ActiveInterpolationsMap.
 static bool isStylePropertyHandle(const PropertyHandle& propertyHandle) {
   return propertyHandle.isCSSProperty() ||
          propertyHandle.isPresentationAttribute();