Oilpan: Remove most WillBe types from the code base

third_party/WebKit/Source/core/animation/AnimationTimelineTest.cpp

Index: third_party/WebKit/Source/core/animation/AnimationTimelineTest.cpp
diff --git a/third_party/WebKit/Source/core/animation/AnimationTimelineTest.cpp b/third_party/WebKit/Source/core/animation/AnimationTimelineTest.cpp
index 820a7f5a0215fa21e6d4d129549c865448f4e94e..975bbaa723f56f0517a5449c8bcb36cb5f99786a 100644
--- a/third_party/WebKit/Source/core/animation/AnimationTimelineTest.cpp
+++ b/third_party/WebKit/Source/core/animation/AnimationTimelineTest.cpp
@@ -89,8 +89,8 @@ protected:
     }
 
     OwnPtr<DummyPageHolder> pageHolder;
-    RefPtrWillBePersistent<Document> document;
-    RefPtrWillBePersistent<Element> element;
+    Persistent<Document> document;
+    Persistent<Element> element;
     Persistent<AnimationTimeline> timeline;
     Timing timing;
     Persistent<MockPlatformTiming> platformTiming;