Mark DOMStringList.contains() as deprecated, add console warning.

LayoutTests/storage/indexeddb/resources/objectstore-basics.js

 if (this.importScripts) {
     importScripts('../../../resources/js-test.js');
     importScripts('shared.js');
 }
 
 description("Test the basics of IndexedDB's IDBObjectStore.");
 
 indexedDBTest(prepareDatabase, testSetVersionAbort);
 function prepareDatabase(evt)
 {
@@ skipping 95 matching lines @@
     shouldBe("db.version", "1");
     shouldBe("store.transaction", "setVersionTrans");
     shouldBe("store.indexNames", "['indexName']");
     shouldBe("store.indexNames.length", "1");
     shouldBe("store.indexNames.contains('')", "false");
     shouldBe("store.indexNames.contains('indexFail')", "false");
     shouldBe("store.indexNames.contains('indexName')", "true");
     shouldBeEqualToString("store.indexNames[0]", "indexName");
     shouldBeUndefined("store.indexNames[1]");
     shouldBeUndefined("store.indexNames[100]");
-    shouldBeNull("store.indexNames.item(1)");
-    shouldBeNull("store.indexNames.item(100)");
 }
 
 var testDate = new Date("August 25, 1991 20:57:08");
 var testDateB = new Date("Wed Jan 05 2011 15:54:49");
 
 function openAgain()
 {
     preamble();
     request = evalAndLog('indexedDB.open(dbname)');
     request.onerror = unexpectedErrorCallback;
@@ skipping 172 matching lines @@
 
         debug("The object store uses in-line keys but no key generator and the result of evaluating the object store's key path does not yield a value.");
         evalAndExpectException("storeWithInLineKeys.add({})", "0", "'DataError'");
 
         debug("The key parameter was provided but does not contain a valid key.");
         evalAndExpectException("storeWithOutOfLineKeys.add({}, null)", "0", "'DataError'");
 
         finishJSTest();
     };
 }