Remove const from createPopupMenu

Source/core/loader/EmptyClients.h

 /*
  * Copyright (C) 2006 Eric Seidel (eric@webkit.org)
  * Copyright (C) 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
  * Copyright (C) 2012 Samsung Electronics. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
@@ skipping 98 matching lines @@
     virtual bool canRunBeforeUnloadConfirmPanel() override { return false; }
     virtual bool runBeforeUnloadConfirmPanel(const String&, LocalFrame*) override { return true; }
 
     virtual void closeWindowSoon() override { }
 
     virtual void runJavaScriptAlert(LocalFrame*, const String&) override { }
     virtual bool runJavaScriptConfirm(LocalFrame*, const String&) override { return false; }
     virtual bool runJavaScriptPrompt(LocalFrame*, const String&, const String&, String&) override { return false; }
 
     virtual bool hasOpenedPopup() const override { return false; }
-    virtual PassRefPtrWillBeRawPtr<PopupMenu> createPopupMenu(LocalFrame&, PopupMenuClient*) const override;
+    virtual PassRefPtrWillBeRawPtr<PopupMenu> createPopupMenu(LocalFrame&, PopupMenuClient*) override;
     virtual DOMWindow* pagePopupWindowForTesting() const override { return nullptr; }
 
     virtual void setStatusbarText(const String&) override { }
 
     virtual bool tabsToLinks() override { return false; }
 
     virtual IntRect windowResizerRect() const override { return IntRect(); }
 
     virtual void invalidateContentsAndRootView(const IntRect&) override { }
     virtual void invalidateContentsForSlowScroll(const IntRect&) override { }
@@ skipping 198 matching lines @@
 public:
     virtual PassOwnPtr<StorageNamespace> createSessionStorageNamespace() override;
     virtual bool canAccessStorage(LocalFrame*, StorageType) const override { return false; }
 };
 
 void fillWithEmptyClients(Page::PageClients&);
 
 }
 
 #endif // EmptyClients_h