Revert of Move all RefPtr's to CSSValue to oilpan transition types, except for the one in CSSCursorImageValue.

Source/core/animation/AnimatableUnknownTest.cpp

Index: Source/core/animation/AnimatableUnknownTest.cpp
diff --git a/Source/core/animation/AnimatableUnknownTest.cpp b/Source/core/animation/AnimatableUnknownTest.cpp
index 2785dfe049751466b705cc487a426335ee2016de..5ca176071084dd2e7e07fac350af80fe89f174a0 100644
--- a/Source/core/animation/AnimatableUnknownTest.cpp
+++ b/Source/core/animation/AnimatableUnknownTest.cpp
@@ -51,10 +51,10 @@
         otherAnimatableUnknown = AnimatableUnknown::create(otherCSSValue);
     }
 
-    RefPtrWillBePersistent<CSSValue> cssValue;
+    RefPtr<CSSValue> cssValue;
     RefPtr<AnimatableValue> animatableUnknown;
 
-    RefPtrWillBePersistent<CSSValue> otherCSSValue;
+    RefPtr<CSSValue> otherCSSValue;
     RefPtr<AnimatableValue> otherAnimatableUnknown;
 };