[Oilpan] Migrate most classes under core/animations to Oilpan heap.

Source/core/animation/LengthBoxStyleInterpolationTest.cpp

Index: Source/core/animation/LengthBoxStyleInterpolationTest.cpp
diff --git a/Source/core/animation/LengthBoxStyleInterpolationTest.cpp b/Source/core/animation/LengthBoxStyleInterpolationTest.cpp
index ca8101992a5b8c2a4dd8909cdf42a3b488267376..6da32e6a5e4f73506c01815722c479765a93d285 100644
--- a/Source/core/animation/LengthBoxStyleInterpolationTest.cpp
+++ b/Source/core/animation/LengthBoxStyleInterpolationTest.cpp
@@ -16,7 +16,7 @@ namespace blink {
 
 class AnimationLengthBoxStyleInterpolationTest : public ::testing::Test {
 protected:
-    static PassOwnPtrWillBeRawPtr<InterpolableValue> lengthBoxToInterpolableValue(const CSSValue& value)
+    static InterpolableValue* lengthBoxToInterpolableValue(const CSSValue& value)
     {
         return LengthBoxStyleInterpolation::lengthBoxtoInterpolableValue(value, value, false);
     }
@@ -28,7 +28,7 @@ protected:
 
     static PassRefPtrWillBeRawPtr<CSSValue> roundTrip(PassRefPtrWillBeRawPtr<CSSValue> value)
     {
-        return interpolableValueToLengthBox(lengthBoxToInterpolableValue(*value).get(), *value, *value);
+        return interpolableValueToLengthBox(lengthBoxToInterpolableValue(*value), *value, *value);
     }
 
     static void testPrimitiveValue(RefPtrWillBeRawPtr<CSSValue> value, double left, double right, double top, double bottom, CSSPrimitiveValue::UnitType unitType)