Oilpan: Replace RefPtrs to Document in core/{accessibility,animation,fetch} with Oilpan transition …

Source/core/animation/AnimationTimelineTest.cpp

Index: Source/core/animation/AnimationTimelineTest.cpp
diff --git a/Source/core/animation/AnimationTimelineTest.cpp b/Source/core/animation/AnimationTimelineTest.cpp
index 3580d35b4fc26ba07f77ae56503b3e920c4b34c3..5417cc80f66acd694f4d33fc09fb2ab5e60d26d7 100644
--- a/Source/core/animation/AnimationTimelineTest.cpp
+++ b/Source/core/animation/AnimationTimelineTest.cpp
@@ -109,7 +109,7 @@ protected:
         timeline->serviceAnimations(TimingUpdateForAnimationFrame);
     }
 
-    RefPtr<Document> document;
+    RefPtrWillBePersistent<Document> document;
     RefPtrWillBePersistent<Element> element;
     RefPtrWillBePersistent<AnimationTimeline> timeline;
     Timing timing;