Make canNavigate() OOPI-friendly

Source/core/html/HTMLFrameOwnerElement.h

 /*
  * Copyright (C) 2006, 2007, 2009 Apple Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 73 matching lines @@
     void setSandboxFlags(SandboxFlags);
 
     bool loadOrRedirectSubframe(const KURL&, const AtomicString& frameName, bool lockBackForwardList, ContentSecurityPolicyDisposition shouldCheckContentSecurityPolicy);
 
 private:
     virtual bool isKeyboardFocusable() const override;
     virtual bool isFrameOwnerElement() const override final { return true; }
 
     // FrameOwner overrides:
     virtual bool isLocal() const { return true; }
-    virtual SandboxFlags sandboxFlags() const override { return m_sandboxFlags; }
+    virtual SandboxFlags sandboxFlags() const override;
     virtual void dispatchLoad() override;
 
     RawPtrWillBeMember<Frame> m_contentFrame;
     RefPtrWillBeMember<Widget> m_widget;
     SandboxFlags m_sandboxFlags;
 };
 
 DEFINE_ELEMENT_TYPE_CASTS(HTMLFrameOwnerElement, isFrameOwnerElement());
 
 class SubframeLoadingDisabler {
@@ skipping 25 matching lines @@
     static WillBeHeapHashCountedSet<RawPtrWillBeMember<Node>>& disabledSubtreeRoots();
 
     RawPtrWillBeMember<Node> m_root;
 };
 
 DEFINE_TYPE_CASTS(HTMLFrameOwnerElement, FrameOwner, owner, owner->isLocal(), owner.isLocal());
 
 } // namespace blink
 
 #endif // HTMLFrameOwnerElement_h