Split out String, URI and CustomIdent from CSSPrimitiveValue

Source/core/animation/DeferredLegacyStyleInterpolation.cpp

Index: Source/core/animation/DeferredLegacyStyleInterpolation.cpp
diff --git a/Source/core/animation/DeferredLegacyStyleInterpolation.cpp b/Source/core/animation/DeferredLegacyStyleInterpolation.cpp
index 3ea8090830a5a655674bf3bccf351e3f292ade05..e814a7b3729bf5c9541f7ebb13b6f6da7a927191 100644
--- a/Source/core/animation/DeferredLegacyStyleInterpolation.cpp
+++ b/Source/core/animation/DeferredLegacyStyleInterpolation.cpp
@@ -48,6 +48,8 @@ bool DeferredLegacyStyleInterpolation::interpolationRequiresStyleResolve(const C
     // FIXME: should not require resolving styles for inherit/initial/unset.
     if (value.isCSSWideKeyword())
         return true;
+    if (value.isStringValue())
+        return false;
     if (value.isPrimitiveValue())
         return interpolationRequiresStyleResolve(toCSSPrimitiveValue(value));
     if (value.isQuadValue())
@@ -69,7 +71,7 @@ bool DeferredLegacyStyleInterpolation::interpolationRequiresStyleResolve(const C
 bool DeferredLegacyStyleInterpolation::interpolationRequiresStyleResolve(const CSSPrimitiveValue& primitiveValue)
 {
     // FIXME: consider other types.
-    if (primitiveValue.isNumber() || primitiveValue.isPercentage() || primitiveValue.isAngle() || primitiveValue.isRGBColor() || primitiveValue.isURI())
+    if (primitiveValue.isNumber() || primitiveValue.isPercentage() || primitiveValue.isAngle() || primitiveValue.isRGBColor())
         return false;
 
     if (primitiveValue.isLength())