Oilpan: have DOMException be on the heap by default.

Source/core/streams/ReadableStream.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 "core/streams/ReadableStream.h"
 
 #include "bindings/core/v8/ExceptionState.h"
 #include "bindings/core/v8/ScriptFunction.h"
 #include "bindings/core/v8/ScriptPromiseResolver.h"
@@ skipping 95 matching lines @@
 
     return cancelInternal(scriptState, reason);
 }
 
 ScriptPromise ReadableStream::cancelInternal(ScriptState* scriptState, ScriptValue reason)
 {
     closeInternal();
     return m_source->cancelSource(scriptState, reason).then(ConstUndefined::create(scriptState));
 }
 
-void ReadableStream::error(PassRefPtrWillBeRawPtr<DOMException> exception)
+void ReadableStream::error(DOMException* exception)
 {
     if (m_state != ReadableStream::Readable)
         return;
 
     m_exception = exception;
     clearQueue();
     rejectAllPendingReads(m_exception);
     m_state = Errored;
     if (m_reader)
         m_reader->releaseLock();
@@ skipping 54 matching lines @@
 }
 
 DEFINE_TRACE(ReadableStream)
 {
     visitor->trace(m_source);
     visitor->trace(m_exception);
     visitor->trace(m_reader);
 }
 
 } // namespace blink