Oilpan: have DOMException be on the heap by default.

Source/core/dom/DOMException.idl

 /*
  * Copyright (C) 2007 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 11 matching lines @@
  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 [
     Exposed=(Window,Worker),
     DoNotCheckConstants,
-    WillBeGarbageCollected,
+    GarbageCollected,
 ] exception DOMException {
 
     readonly attribute unsigned short   code;
     readonly attribute DOMString        name;
     readonly attribute DOMString        message;
 
     // Override in a Mozilla compatible format
     [NotEnumerable] DOMString toString();
 
     // ExceptionCode
@@ skipping 28 matching lines @@
     const unsigned short      ABORT_ERR                      = 20;
     const unsigned short      URL_MISMATCH_ERR               = 21;
     const unsigned short      QUOTA_EXCEEDED_ERR             = 22;
     // TIMEOUT_ERR is currently unused but was added for completeness.
     const unsigned short      TIMEOUT_ERR                    = 23;
     // INVALID_NODE_TYPE_ERR is currently unused but was added for completeness.
     const unsigned short      INVALID_NODE_TYPE_ERR          = 24;
     const unsigned short      DATA_CLONE_ERR                 = 25;
 };