Oilpan: fix build after r202439.

Source/core/animation/LengthInterpolationType.cpp

Index: Source/core/animation/LengthInterpolationType.cpp
diff --git a/Source/core/animation/LengthInterpolationType.cpp b/Source/core/animation/LengthInterpolationType.cpp
index 21214df6aaa246417095aa397b9a21fc56ef643f..87cd56e4f150af11b310bf63930d50b7064fde6d 100644
--- a/Source/core/animation/LengthInterpolationType.cpp
+++ b/Source/core/animation/LengthInterpolationType.cpp
@@ -18,13 +18,13 @@ namespace blink {
 class LengthNonInterpolableValue : public NonInterpolableValue {
 public:
     ~LengthNonInterpolableValue() override { ASSERT_NOT_REACHED(); }
-    static PassRefPtr<LengthNonInterpolableValue> create(bool hasPercentage)
+    static PassRefPtrWillBeRawPtr<LengthNonInterpolableValue> create(bool hasPercentage)
     {
-        DEFINE_STATIC_REF_WILL_BE_PERSISTENT(LengthNonInterpolableValue, singleton, adoptRef(new LengthNonInterpolableValue()));
+        DEFINE_STATIC_REF_WILL_BE_PERSISTENT(LengthNonInterpolableValue, singleton, adoptRefWillBeNoop(new LengthNonInterpolableValue()));
         ASSERT(singleton);
         return hasPercentage ? singleton : nullptr;
     }
-    static PassRefPtr<LengthNonInterpolableValue> merge(const NonInterpolableValue* a, const NonInterpolableValue* b)
+    static PassRefPtrWillBeRawPtr<LengthNonInterpolableValue> merge(const NonInterpolableValue* a, const NonInterpolableValue* b)
     {
         return create(hasPercentage(a) || hasPercentage(b));
     }