IndexedDB: Log exception messages

LayoutTests/storage/indexeddb/open-cursor-expected.txt

 Test IndexedDB's openCursor.
 
 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 = "open-cursor.html"
 indexedDB.deleteDatabase(dbname)
 indexedDB.open(dbname)
 objectStore = db.createObjectStore('test')
 objectStore.add('myValue', 'myKey')
 Opening cursor
 event.target.source.openCursor(keyRange)
 Cursor opened successfully.
 PASS cursor.direction is "next"
 PASS cursor.key is "myKey"
 PASS cursor.value is "myValue"
 
 Passing an invalid key into .continue({}).
 Expecting exception from event.target.result.continue({})
 PASS Exception was thrown.
 PASS code is 0
 PASS ename is 'DataError'
+Exception message: The parameter is not a valid key.
 
 Opening an empty cursor.
 objectStore.openCursor(keyRange)
 Empty cursor opened successfully.
 PASS cursor is null
 Opening cursor
 event.target.source.openCursor("myKey")
 Cursor opened successfully.
 PASS cursor.direction is "next"
 PASS cursor.key is "myKey"
 PASS cursor.value is "myValue"
 
 Passing an invalid key into .continue({}).
 Expecting exception from cursor.continue({})
 PASS Exception was thrown.
 PASS code is 0
 PASS ename is 'DataError'
+Exception message: The parameter is not a valid key.
 
 Opening an empty cursor.
 objectStore.openCursor("InexistentKey")
 Empty cursor opened successfully.
 PASS cursor is null
 PASS successfullyParsed is true
 
 TEST COMPLETE