Oilpan: have DOMException be on the heap by default.

Source/modules/vr/NavigatorVRDevice.cpp

Index: Source/modules/vr/NavigatorVRDevice.cpp
diff --git a/Source/modules/vr/NavigatorVRDevice.cpp b/Source/modules/vr/NavigatorVRDevice.cpp
index d69b509d497fce8b9531a78ae3eabc94ad5fe4c3..682dc2a0b8aeb26f1ddf1f614b5a8f82fccad825 100644
--- a/Source/modules/vr/NavigatorVRDevice.cpp
+++ b/Source/modules/vr/NavigatorVRDevice.cpp
@@ -54,7 +54,7 @@ ScriptPromise NavigatorVRDevice::getVRDevices(ScriptState* scriptState)
     Document* document = m_frame ? m_frame->document() : 0;
 
     if (!document || !controller()) {
-        RefPtrWillBeRawPtr<DOMException> exception = DOMException::create(InvalidStateError, "The object is no longer associated to a document.");
+        DOMException* exception = DOMException::create(InvalidStateError, "The object is no longer associated to a document.");
         resolver->reject(exception);
         return promise;
     }