Use WebIDBKeyPath type in WebKit API, implement IndexedDBKeyPath type.

content/ppapi_plugin/ppapi_webkitplatformsupport_impl.cc

Index: content/ppapi_plugin/ppapi_webkitplatformsupport_impl.cc
diff --git a/content/ppapi_plugin/ppapi_webkitplatformsupport_impl.cc b/content/ppapi_plugin/ppapi_webkitplatformsupport_impl.cc
index 6aec56cfc843df4bd8c6d5b2fa8879bcff92eb34..56ee6a584a29f4b0ad1d99259c77afcd7fe38df8 100644
--- a/content/ppapi_plugin/ppapi_webkitplatformsupport_impl.cc
+++ b/content/ppapi_plugin/ppapi_webkitplatformsupport_impl.cc
@@ -241,7 +241,7 @@ int PpapiWebKitPlatformSupportImpl::databaseDeleteFile(
 
 void PpapiWebKitPlatformSupportImpl::createIDBKeysFromSerializedValuesAndKeyPath(
     const WebKit::WebVector<WebKit::WebSerializedScriptValue>& values,
-    const WebKit::WebString& keyPath,
+    const WebKit::WebIDBKeyPath& keyPath,
     WebKit::WebVector<WebKit::WebIDBKey>& keys) {
   NOTREACHED();
 }
@@ -250,7 +250,7 @@ WebKit::WebSerializedScriptValue
 PpapiWebKitPlatformSupportImpl::injectIDBKeyIntoSerializedValue(
     const WebKit::WebIDBKey& key,
     const WebKit::WebSerializedScriptValue& value,
-    const WebKit::WebString& keyPath) {
+    const WebKit::WebIDBKeyPath& keyPath) {
   NOTREACHED();
   return WebKit::WebSerializedScriptValue();
 }