Oilpan: fix build after r182644.

Source/modules/encryptedmedia/HTMLMediaElementEncryptedMedia.cpp

 // Copyright 2014 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.
 
 #include "config.h"
 #include "modules/encryptedmedia/HTMLMediaElementEncryptedMedia.h"
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptPromise.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
@@ skipping 45 matching lines @@
 private:
     SetMediaKeysHandler(ScriptState*, HTMLMediaElement&, MediaKeys*);
     void timerFired(Timer<SetMediaKeysHandler>*);
 
     void clearExistingMediaKeys();
     void setNewMediaKeys();
     void finish();
 
     void reportSetFailed(ExceptionCode, const String& errorMessage);
 
-    RawPtrWillBeMember<HTMLMediaElement> m_element;
+    // Keep media element alive until promise is fulfilled
+    RefPtrWillBePersistent<HTMLMediaElement> m_element;
     Persistent<MediaKeys> m_newMediaKeys;
     Timer<SetMediaKeysHandler> m_timer;
 };
 
 typedef Function<void()> SuccessCallback;
 typedef Function<void(ExceptionCode, const String&)> FailureCallback;
 
 // Represents the result used when setContentDecryptionModule() is called.
 // Calls |success| if result is resolved, |failure| is result is rejected.
 class SetContentDecryptionModuleResult FINAL : public ContentDecryptionModuleResult {
@@ skipping 463 matching lines @@
     return thisElement.contentDecryptionModule();
 }
 
 void HTMLMediaElementEncryptedMedia::trace(Visitor* visitor)
 {
     visitor->trace(m_mediaKeys);
     WillBeHeapSupplement<HTMLMediaElement>::trace(visitor);
 }
 
 } // namespace blink