Extension Storage API: expose storage quota information to extensions, via:

chrome/browser/extensions/extension_function_dispatcher.cc

 // Copyright (c) 2012 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/extensions/extension_function_dispatcher.h"
 
 #include <map>
 
 #include "base/json/json_value_serializer.h"
 #include "base/memory/ref_counted.h"
@@ skipping 425 matching lines @@
   // Debugger
   RegisterFunction<AttachDebuggerFunction>();
   RegisterFunction<DetachDebuggerFunction>();
   RegisterFunction<SendCommandDebuggerFunction>();
 
   // Settings
   RegisterFunction<extensions::GetSettingsFunction>();
   RegisterFunction<extensions::SetSettingsFunction>();
   RegisterFunction<extensions::RemoveSettingsFunction>();
   RegisterFunction<extensions::ClearSettingsFunction>();
+  RegisterFunction<extensions::GetBytesInUseSettingsFunction>();
 
   // Content settings.
   RegisterFunction<GetResourceIdentifiersFunction>();
   RegisterFunction<ClearContentSettingsFunction>();
   RegisterFunction<GetContentSettingFunction>();
   RegisterFunction<SetContentSettingFunction>();
 
   // ChromeAuth settings.
   RegisterFunction<SetCloudPrintCredentialsFunction>();
 
@@ skipping 302 matching lines @@
   return function;
 }
 
 // static
 void ExtensionFunctionDispatcher::SendAccessDenied(
     IPC::Message::Sender* ipc_sender, int routing_id, int request_id) {
   ipc_sender->Send(new ExtensionMsg_Response(
       routing_id, request_id, false, std::string(),
       "Access to extension API denied."));
 }