Structured cloning: improve DataCloneError reporting.

LayoutTests/storage/indexeddb/exceptions-expected.txt

 Test that expected exceptions are thrown per IndexedDB spec.
 
 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
 
 
 indexedDB = self.indexedDB || self.webkitIndexedDB || self.mozIndexedDB || self.msIndexedDB || self.OIndexedDB;
 
 dbname = "exceptions.html"
 indexedDB.deleteDatabase(dbname)
 indexedDB.open(dbname)
@@ skipping 142 matching lines @@
 The transaction this IDBObjectStore belongs to is not active.
 Expecting exception from storeFromInactiveTransaction.add(0, 0)
 PASS Exception was thrown.
 PASS code is 0
 PASS ename is 'TransactionInactiveError'
 Exception message: Failed to execute 'add' on 'IDBObjectStore': The transaction has finished.
 The data being stored could not be cloned by the internal structured cloning algorithm.
 Expecting exception from store.add(self, 0)
 PASS Exception was thrown.
 PASS code is DOMException.DATA_CLONE_ERR
-Exception message: An object could not be cloned.
+Exception message: Failed to execute 'add' on 'IDBObjectStore': An object could not be cloned.
 
 IDBObjectStore.clear()
 This method throws a DOMException of type ReadOnlyError if the transaction which this IDBObjectStore belongs to is has its mode set to "readonly".
 Expecting exception from storeFromReadOnlyTransaction.clear()
 PASS Exception was thrown.
 PASS code is 0
 PASS ename is 'ReadOnlyError'
 Exception message: A write operation was attempted in a read-only transaction.
 The transaction this IDBObjectStore belongs to is not active.
 Expecting exception from storeFromInactiveTransaction.clear()
@@ skipping 110 matching lines @@
 The transaction this IDBObjectStore belongs to is not active.
 Expecting exception from storeFromInactiveTransaction.put(0, 0)
 PASS Exception was thrown.
 PASS code is 0
 PASS ename is 'TransactionInactiveError'
 Exception message: Failed to execute 'put' on 'IDBObjectStore': The transaction has finished.
 The data being stored could not be cloned by the internal structured cloning algorithm.
 Expecting exception from store.put(self, 0)
 PASS Exception was thrown.
 PASS code is DOMException.DATA_CLONE_ERR
-Exception message: An object could not be cloned.
+Exception message: Failed to execute 'put' on 'IDBObjectStore': An object could not be cloned.
 db.close()
 ro_transaction.oncomplete = transactionComplete
 rw_transaction.oncomplete = transactionComplete
 
 transactionComplete():
 First transaction completed
 
 transactionComplete():
 request = indexedDB.open(dbname, 3)
 request.onupgradeneeded = onUpgradeNeeded3
@@ skipping 211 matching lines @@
 If the effective object store of this cursor uses in-line keys and evaluating the key path of the value parameter results in a different value than the cursor's effective key, this method throws a DOMException of type DataError.
 Expecting exception from inlineCursor.update({id: 1})
 PASS Exception was thrown.
 PASS code is 0
 PASS ename is 'DataError'
 Exception message: Failed to execute 'update' on 'IDBCursor': The effective object store of this cursor uses in-line keys and evaluating the key path of the value parameter results in a different value than the cursor's effective key.
 If the structured clone algorithm throws an exception, that exception is rethrown.
 Expecting exception from cursor.update(self)
 PASS Exception was thrown.
 PASS code is DOMException.DATA_CLONE_ERR
-Exception message: An object could not be cloned.
+Exception message: Failed to execute 'update' on 'IDBCursor': An object could not be cloned.
 The transaction this IDBCursor belongs to is not active.
 Expecting exception from cursorFromInactiveTransaction.update({})
 PASS Exception was thrown.
 PASS code is 0
 PASS ename is 'TransactionInactiveError'
 Exception message: Failed to execute 'update' on 'IDBCursor': The transaction has finished.
 readOnlyTransaction = db.transaction('store', 'readonly')
 request = readOnlyTransaction.objectStore('store').openCursor()
 cursorFromReadOnlyTransaction = request.result
 
@@ skipping 25 matching lines @@
 If the requested object store is not in this transaction's scope.
 Expecting exception from db.transaction('store').objectStore('otherStore')
 PASS Exception was thrown.
 PASS code is DOMException.NOT_FOUND_ERR
 PASS ename is 'NotFoundError'
 Exception message: Failed to execute 'objectStore' on 'IDBTransaction': The specified object store was not found.
 PASS successfullyParsed is true
 
 TEST COMPLETE