Use WebIDBKeyPath type in WebKit API, implement IndexedDBKeyPath type.

content/common/utility_messages.h

 // 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.
 
 // Multiply-included message file, so no include guard.
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "content/common/content_export.h"
 #include "content/common/indexed_db/indexed_db_key.h"
+#include "content/common/indexed_db/indexed_db_key_path.h"
 #include "content/common/indexed_db/indexed_db_param_traits.h"
 #include "content/public/common/common_param_traits.h"
 #include "content/public/common/serialized_script_value.h"
 #include "ipc/ipc_message_macros.h"
 #include "webkit/plugins/webplugininfo.h"
 
 #undef IPC_MESSAGE_EXPORT
 #define IPC_MESSAGE_EXPORT CONTENT_EXPORT
 #define IPC_MESSAGE_START UtilityMsgStart
 
 //------------------------------------------------------------------------------
 // Utility process messages:
 // These are messages from the browser to the utility process.
 
 // Tell the utility process to extract the given IDBKeyPath from the
 // SerializedScriptValue vector and reply with the corresponding IDBKeys.
 IPC_MESSAGE_CONTROL3(UtilityMsg_IDBKeysFromValuesAndKeyPath,
                      int,     // id
                      std::vector<content::SerializedScriptValue>,
-                     string16)  // IDBKeyPath
+                     IndexedDBKeyPath)
 
 IPC_MESSAGE_CONTROL3(UtilityMsg_InjectIDBKey,
                      IndexedDBKey /* key */,
                      content::SerializedScriptValue /* value */,
-                     string16 /* key path*/)
+                     IndexedDBKeyPath)
 
 // Tells the utility process that it's running in batch mode.
 IPC_MESSAGE_CONTROL0(UtilityMsg_BatchMode_Started)
 
 // Tells the utility process that it can shutdown.
 IPC_MESSAGE_CONTROL0(UtilityMsg_BatchMode_Finished)
 
 #if defined(OS_POSIX)
 // Tells the utility process to load each plugin in the order specified by the
 // vector. It will respond after each load with the WebPluginInfo.
@@ skipping 26 matching lines @@
 // keep the canonical list in sync.
 IPC_SYNC_MESSAGE_CONTROL2_0(UtilityHostMsg_LoadPluginFailed,
                             uint32_t /* index in the vector */,
                             FilePath /* path of plugin */)
 
 // Notifies the browser that a plugin in the vector sent by it has been loaded.
 IPC_SYNC_MESSAGE_CONTROL2_0(UtilityHostMsg_LoadedPlugin,
                             uint32_t /* index in the vector */,
                             webkit::WebPluginInfo /* plugin info */)
 #endif  // OS_POSIX