Use WebIDBKeyPath type in WebKit API, implement IndexedDBKeyPath type.

content/utility/utility_thread_impl.h

 // Copyright (c) 2011 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.
 
 #ifndef CONTENT_UTILITY_UTILITY_THREAD_IMPL_H_
 #define CONTENT_UTILITY_UTILITY_THREAD_IMPL_H_
 #pragma once
 
 #include <string>
 #include <vector>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
-#include "base/string16.h"
 #include "content/common/child_thread.h"
 #include "content/common/content_export.h"
 #include "content/public/utility/utility_thread.h"
 
 class FilePath;
 class IndexedDBKey;
 
 namespace content {
+class IndexedDBKeyPath;
 class SerializedScriptValue;
 class WebKitPlatformSupportImpl;
 }
 
 // This class represents the background thread where the utility task runs.
 class UtilityThreadImpl : public content::UtilityThread,
                           public ChildThread {
  public:
   UtilityThreadImpl();
   virtual ~UtilityThreadImpl();
 
   virtual bool Send(IPC::Message* msg) OVERRIDE;
   virtual void ReleaseProcessIfNeeded() OVERRIDE;
 #if defined(OS_WIN)
   virtual void PreCacheFont(const LOGFONT& log_font) OVERRIDE;
   virtual void ReleaseCachedFonts() OVERRIDE;
 #endif
 
  private:
   // ChildThread implementation.
   virtual bool OnControlMessageReceived(const IPC::Message& msg) OVERRIDE;
 
   // IPC message handlers.
   void OnIDBKeysFromValuesAndKeyPath(
       int id,
       const std::vector<content::SerializedScriptValue>&
           serialized_script_values,
-      const string16& idb_key_path);
+      const content::IndexedDBKeyPath& idb_key_path);
   void OnInjectIDBKey(const IndexedDBKey& key,
                       const content::SerializedScriptValue& value,
-                      const string16& key_path);
+                      const content::IndexedDBKeyPath& key_path);
   void OnBatchModeStarted();
   void OnBatchModeFinished();
 
 #if defined(OS_POSIX)
   void OnLoadPlugins(const std::vector<FilePath>& plugin_paths);
 #endif  // OS_POSIX
 
   // True when we're running in batch mode.
   bool batch_mode_;
 
   scoped_ptr<content::WebKitPlatformSupportImpl> webkit_platform_support_;
 
   DISALLOW_COPY_AND_ASSIGN(UtilityThreadImpl);
 };
 
 #endif  // CONTENT_UTILITY_UTILITY_THREAD_IMPL_H_