Use WebIDBKeyPath type in WebKit API, implement IndexedDBKeyPath type.

content/common/indexed_db/proxy_webidbindex_impl.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.
 
 #ifndef CONTENT_COMMON_INDEXED_DB_PROXY_WEBIDBINDEX_IMPL_H_
 #define CONTENT_COMMON_INDEXED_DB_PROXY_WEBIDBINDEX_IMPL_H_
 #pragma once
 
 #include "base/basictypes.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebIDBCallbacks.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/WebIDBIndex.h"
 
 class RendererWebIDBIndexImpl : public WebKit::WebIDBIndex {
  public:
   explicit RendererWebIDBIndexImpl(int32 idb_index_id);
   virtual ~RendererWebIDBIndexImpl();
 
   // WebKit::WebIDBIndex
   virtual WebKit::WebString name() const;
   virtual WebKit::WebString storeName() const;
-  virtual WebKit::WebString keyPathString() const;
+  virtual WebKit::WebIDBKeyPath keyPath() const;
   virtual bool unique() const;
   virtual bool multiEntry() const;
 
   virtual void openObjectCursor(const WebKit::WebIDBKeyRange& range,
                                 unsigned short direction,
                                 WebKit::WebIDBCallbacks* callbacks,
                                 const WebKit::WebIDBTransaction& transaction,
                                 WebKit::WebExceptionCode& ec);
   virtual void openKeyCursor(const WebKit::WebIDBKeyRange& range,
                              unsigned short direction,
@@ skipping 19 matching lines @@
   virtual void getKey(const WebKit::WebIDBKeyRange& key_range,
                       WebKit::WebIDBCallbacks* callbacks,
                       const WebKit::WebIDBTransaction& transaction,
                       WebKit::WebExceptionCode& ec);
 
  private:
   int32 idb_index_id_;
 };
 
 #endif  // CONTENT_COMMON_INDEXED_DB_PROXY_WEBIDBINDEX_IMPL_H_