Oilpan: Remove most WillBe types from the code base

third_party/WebKit/Source/web/tests/FrameTestHelpers.h

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 166 matching lines @@
 
     // WebRemoteFrameClient overrides:
     void frameDetached(DetachType) override;
     void postMessageEvent(
         WebLocalFrame* sourceFrame,
         WebRemoteFrame* targetFrame,
         WebSecurityOrigin targetOrigin,
         WebDOMMessageEvent) override { }
 
 private:
-    RawPtrWillBePersistent<WebRemoteFrameImpl> const m_frame;
+    Persistent<WebRemoteFrameImpl> const m_frame;
 };
 
 } // namespace FrameTestHelpers
 } // namespace blink
 
 #endif // FrameTestHelpers_h