Oilpan: Remove most WillBe types from the code base

third_party/WebKit/Source/platform/ThreadedDataReceiver.h

 // Copyright (c) 2015 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef ThreadedDataReceiver_h
 #define ThreadedDataReceiver_h
 
 #include "platform/heap/Handle.h"
 
 namespace blink {
 
 class WebThread;
 
-class ThreadedDataReceiver : public WillBeGarbageCollectedMixin {
+class ThreadedDataReceiver : public GarbageCollectedMixin {
 public:
     virtual ~ThreadedDataReceiver() { }
 
 #if !ENABLE(OILPAN)
     virtual void ref() = 0;
     virtual void deref() = 0;
 #endif
 
     virtual void acceptData(const char* data, int dataLength) = 0;
     virtual WebThread* backgroundThread() = 0;
 
     virtual bool needsMainthreadDataCopy() = 0;
     virtual void acceptMainthreadDataNotification(const char* data, int dataLength, int encodedDataLength) = 0;
 };
 
 } // namespace blink
 
 #endif // ThreadedDataReceiver_h