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

public/web/WebStorageQuotaError.h

Index: public/web/WebStorageQuotaError.h
diff --git a/public/web/WebStorageQuotaError.h b/public/web/WebStorageQuotaError.h
index d2c44c50aef884fc8553548e2614892e3b505411..520fc0afe3b0342b53353208c7ba8e0025d304b3 100644
--- a/public/web/WebStorageQuotaError.h
+++ b/public/web/WebStorageQuotaError.h
@@ -35,10 +35,10 @@ 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