Oilpan: have DOMException be on the heap by default.

Source/modules/fetch/BodyStreamBufferTest.cpp

Index: Source/modules/fetch/BodyStreamBufferTest.cpp
diff --git a/Source/modules/fetch/BodyStreamBufferTest.cpp b/Source/modules/fetch/BodyStreamBufferTest.cpp
index cc24b1d39b3a8bed9eefb85743e5759940c4e7b9..eb017463b30358ac63ac68db8eaa211bbaafba84 100644
--- a/Source/modules/fetch/BodyStreamBufferTest.cpp
+++ b/Source/modules/fetch/BodyStreamBufferTest.cpp
@@ -60,7 +60,7 @@ public:
     {
         m_blobHandle = blobHandle;
     }
-    virtual void didFail(PassRefPtrWillBeRawPtr<DOMException> exception) override
+    virtual void didFail(DOMException* exception) override
     {
         m_exception = exception;
     }
@@ -68,14 +68,14 @@ public:
     {
         return m_blobHandle;
     }
-    PassRefPtrWillBeRawPtr<DOMException> exception()
+    DOMException* exception()
     {
         return m_exception;
     }
 
 private:
     RefPtr<BlobDataHandle> m_blobHandle;
-    RefPtrWillBeMember<DOMException> m_exception;
+    Member<DOMException> m_exception;
 };
 
 class MockCanceller : public BodyStreamBuffer::Canceller {