Clean up some old TODOs

chrome/renderer/renderer_webidbobjectstore_impl.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/renderer/renderer_webidbobjectstore_impl.h"
 
 #include "chrome/common/indexed_db_messages.h"
 #include "chrome/common/serialized_script_value.h"
 #include "chrome/renderer/indexed_db_dispatcher.h"
 #include "chrome/renderer/render_thread.h"
@@ skipping 16 matching lines @@
 using WebKit::WebIDBTransaction;
 using WebKit::WebSerializedScriptValue;
 using WebKit::WebString;
 
 RendererWebIDBObjectStoreImpl::RendererWebIDBObjectStoreImpl(
     int32 idb_object_store_id)
     : idb_object_store_id_(idb_object_store_id) {
 }
 
 RendererWebIDBObjectStoreImpl::~RendererWebIDBObjectStoreImpl() {
+  // It's not possible for there to be pending callbacks that address this
+  // object since inside WebKit, they hold a reference to the object wich owns
+  // this object. But, if that ever changed, then we'd need to invalidate
+  // any such pointers.
   RenderThread::current()->Send(
       new IndexedDBHostMsg_ObjectStoreDestroyed(idb_object_store_id_));
 }
 
 WebString RendererWebIDBObjectStoreImpl::name() const {
   string16 result;
   RenderThread::current()->Send(
       new IndexedDBHostMsg_ObjectStoreName(idb_object_store_id_, &result));
   return result;
 }
@@ skipping 101 matching lines @@
     const WebIDBKeyRange& idb_key_range,
     unsigned short direction, WebIDBCallbacks* callbacks,
     const WebIDBTransaction& transaction,
     WebExceptionCode& ec) {
   IndexedDBDispatcher* dispatcher =
       RenderThread::current()->indexed_db_dispatcher();
   dispatcher->RequestIDBObjectStoreOpenCursor(
       idb_key_range, direction, callbacks,  idb_object_store_id_,
       transaction, &ec);
 }