Use WebIDBKeyPath type in WebKit API, implement IndexedDBKeyPath type.

content/ppapi_plugin/ppapi_webkitplatformsupport_impl.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 "content/ppapi_plugin/ppapi_webkitplatformsupport_impl.h"
 
 #include <map>
 
 #include "base/synchronization/lock.h"
 #include "base/logging.h"
@@ skipping 223 matching lines @@
 }
 
 int PpapiWebKitPlatformSupportImpl::databaseDeleteFile(
     const WebKit::WebString& vfs_file_name, bool sync_dir) {
   NOTREACHED();
   return 0;
 }
 
 void PpapiWebKitPlatformSupportImpl::createIDBKeysFromSerializedValuesAndKeyPath(
     const WebKit::WebVector<WebKit::WebSerializedScriptValue>& values,
-    const WebKit::WebString& keyPath,
+    const WebKit::WebIDBKeyPath& keyPath,
     WebKit::WebVector<WebKit::WebIDBKey>& keys) {
   NOTREACHED();
 }
 
 WebKit::WebSerializedScriptValue
 PpapiWebKitPlatformSupportImpl::injectIDBKeyIntoSerializedValue(
     const WebKit::WebIDBKey& key,
     const WebKit::WebSerializedScriptValue& value,
-    const WebKit::WebString& keyPath) {
+    const WebKit::WebIDBKeyPath& keyPath) {
   NOTREACHED();
   return WebKit::WebSerializedScriptValue();
 }