Add a nullable string16 class to base. It combines a string16 + a null param...

chrome/browser/in_process_webkit/dom_storage_dispatcher_host.cc

 // Copyright (c) 2009 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/browser/in_process_webkit/dom_storage_dispatcher_host.h"
 
+#include "base/nullable_string16.h"
 #include "base/stl_util-inl.h"
-#include "base/string16.h"
 #include "chrome/browser/chrome_thread.h"
 #include "chrome/browser/in_process_webkit/webkit_context.h"
 #include "chrome/browser/in_process_webkit/webkit_thread.h"
 #include "chrome/common/render_messages.h"
 #include "webkit/api/public/WebKit.h"
 #include "webkit/api/public/WebStorageArea.h"
 #include "webkit/api/public/WebStorageNamespace.h"
 #include "webkit/api/public/WebString.h"
 #include "webkit/glue/webkit_glue.h"
 
@@ skipping 237 matching lines @@
   if (ChromeThread::CurrentlyOn(ChromeThread::IO)) {
     MessageLoop* webkit_loop = webkit_thread_->GetMessageLoop();
     webkit_loop->PostTask(FROM_HERE, NewRunnableMethod(this,
         &DOMStorageDispatcherHost::OnKey, storage_area_id, index, reply_msg));
     return;
   }
 
   DCHECK(ChromeThread::CurrentlyOn(ChromeThread::WEBKIT));
   WebStorageArea* storage_area = GetStorageArea(storage_area_id);
   CHECK(storage_area);  // TODO(jorlow): Do better than this.
-  WebString key = storage_area->key(index);
-  ViewHostMsg_DOMStorageKey::WriteReplyParams(reply_msg, (string16)key,
-                                              key.isNull());
+  const NullableString16& key = storage_area->key(index);
+  ViewHostMsg_DOMStorageKey::WriteReplyParams(reply_msg, key);
   Send(reply_msg);
 }
 
 void DOMStorageDispatcherHost::OnGetItem(int64 storage_area_id,
                                          const string16& key,
                                          IPC::Message* reply_msg) {
   DCHECK(!shutdown_);
   if (ChromeThread::CurrentlyOn(ChromeThread::IO)) {
     MessageLoop* webkit_loop = webkit_thread_->GetMessageLoop();
     webkit_loop->PostTask(FROM_HERE, NewRunnableMethod(this,
         &DOMStorageDispatcherHost::OnGetItem,
         storage_area_id, key, reply_msg));
     return;
   }
 
   DCHECK(ChromeThread::CurrentlyOn(ChromeThread::WEBKIT));
   WebStorageArea* storage_area = GetStorageArea(storage_area_id);
   CHECK(storage_area);  // TODO(jorlow): Do better than this.
-  WebString value = storage_area->getItem(key);
-  ViewHostMsg_DOMStorageGetItem::WriteReplyParams(reply_msg, (string16)value,
-                                                  value.isNull());
+  const NullableString16& value = storage_area->getItem(key);
+  ViewHostMsg_DOMStorageGetItem::WriteReplyParams(reply_msg, value);
   Send(reply_msg);
 }
 
 void DOMStorageDispatcherHost::OnSetItem(int64 storage_area_id,
                                          const string16& key,
                                          const string16& value) {
   DCHECK(!shutdown_);
   if (ChromeThread::CurrentlyOn(ChromeThread::IO)) {
     MessageLoop* webkit_loop = webkit_thread_->GetMessageLoop();
     webkit_loop->PostTask(FROM_HERE, NewRunnableMethod(this,
@@ skipping 78 matching lines @@
   return new_namespace_id;
 }
 
 WebString DOMStorageDispatcherHost::GetLocalStoragePath() {
   const FilePath& path = webkit_context_->data_path();
   if (path.empty())
     return WebString();
   FilePath::StringType path_string = path.AppendASCII("localStorage").value();
   return webkit_glue::FilePathStringToWebString(path_string);
 }