Oilpan: have DOMException be on the heap by default.

Source/modules/background_sync/SyncError.cpp

 // Copyright 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.
 
 #include "config.h"
 #include "modules/background_sync/SyncError.h"
 
+#include "core/dom/DOMException.h"
 #include "core/dom/ExceptionCode.h"
 #include "wtf/OwnPtr.h"
 
 namespace blink {
 
-PassRefPtrWillBeRawPtr<DOMException> SyncError::take(ScriptPromiseResolver*, WebType* webErrorRaw)
+DOMException* SyncError::take(ScriptPromiseResolver*, WebType* webErrorRaw)
 {
     OwnPtr<WebType> webError = adoptPtr(webErrorRaw);
     switch (webError->errorType) {
     case WebSyncError::ErrorTypeAbort:
         return DOMException::create(AbortError, webError->message);
     case WebSyncError::ErrorTypeNoPermission:
         return DOMException::create(InvalidAccessError, webError->message);
     case WebSyncError::ErrorTypeNotFound:
         return DOMException::create(NotFoundError, webError->message);
     case WebSyncError::ErrorTypeUnknown:
         return DOMException::create(UnknownError, webError->message);
     }
     ASSERT_NOT_REACHED();
     return DOMException::create(UnknownError);
 }
 
 void SyncError::dispose(WebType* webErrorRaw)
 {
     delete webErrorRaw;
 }
 
 } // namespace blink