Make ExceptionCode be an enum that does not encode the "code" property

public/web/WebStorageQuotaError.h

 /*
  * Copyright (C) 2011 Google 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:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 17 matching lines @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
 #ifndef WebStorageQuotaError_h
 #define WebStorageQuotaError_h
 
 namespace WebKit {
 
 // The error code used for WebStorageQuota.
 enum WebStorageQuotaError {
-    WebStorageQuotaErrorNotSupported = 9,
-    WebStorageQuotaErrorInvalidModification = 13,
-    WebStorageQuotaErrorInvalidAccess = 15,
-    WebStorageQuotaErrorAbort = 20,
+    WebStorageQuotaErrorNotSupported = 7,
+    WebStorageQuotaErrorInvalidModification = 11,
+    WebStorageQuotaErrorInvalidAccess = 13,
+    WebStorageQuotaErrorAbort = 17,
 };
 
 } // namespace WebKit
 
 #endif // WebStorageQuotaError_h