Lazily generate HistoryItem's serialized form state

Source/web/WebHistoryItem.cpp

Index: Source/web/WebHistoryItem.cpp
diff --git a/Source/web/WebHistoryItem.cpp b/Source/web/WebHistoryItem.cpp
index ca1f6776e660937e34f6e596ffc004f0ceb94ca2..dab27ef21fd5cb8237391142259ddc00315b14d5 100644
--- a/Source/web/WebHistoryItem.cpp
+++ b/Source/web/WebHistoryItem.cpp
@@ -33,7 +33,6 @@
 
 #include "WebSerializedScriptValue.h"
 #include "bindings/v8/SerializedScriptValue.h"
-#include "core/html/forms/FormController.h"
 #include "core/loader/HistoryItem.h"
 #include "platform/network/FormData.h"
 #include "platform/weborigin/KURL.h"
@@ -59,7 +58,7 @@ void addReferencedFilePaths(HistoryItem* item, HashSet<String>& results)
         }
     }
 
-    const Vector<String>& filePaths = FormController::getReferencedFilePaths(item->documentState());
+    const Vector<String>& filePaths = item->getReferencedFilePaths();
     for (size_t i = 0; i < filePaths.size(); ++i)
         results.add(filePaths[i]);