Oilpan: Remove most WillBe types from the code base

third_party/WebKit/Source/modules/webaudio/MediaElementAudioSourceNode.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:
  * 1.  Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 54 matching lines @@
 
     // Must be called only on the main thread.
     bool passesCurrentSrcCORSAccessCheck(const KURL& currentSrc);
 
     // Print warning if CORS restrictions cause MediaElementAudioSource to output zeroes.
     void printCORSMessage(const String& message);
 
     // This Persistent doesn't make a reference cycle. The reference from
     // HTMLMediaElement to AudioSourceProvideClient, which
     // MediaElementAudioSourceNode implements, is weak.
-    RefPtrWillBePersistent<HTMLMediaElement> m_mediaElement;
+    Persistent<HTMLMediaElement> m_mediaElement;
     Mutex m_processLock;
 
     unsigned m_sourceNumberOfChannels;
     double m_sourceSampleRate;
 
     OwnPtr<MultiChannelResampler> m_multiChannelResampler;
 
     // |m_passesCurrentSrcCORSAccessCheck| holds the value of
     // context()->getSecurityOrigin() && context()->getSecurityOrigin()->canRequest(mediaElement()->currentSrc()),
     // updated in the ctor and onCurrentSrcChanged() on the main thread and
@@ skipping 26 matching lines @@
     void lock() override;
     void unlock() override;
 
 private:
     MediaElementAudioSourceNode(AbstractAudioContext&, HTMLMediaElement&);
 };
 
 } // namespace blink
 
 #endif // MediaElementAudioSourceNode_h