Implement NavigationThrottle::BLOCK_REQUEST_AND_COLLAPSE.

third_party/WebKit/Source/core/html/HTMLIFrameElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Simon Hausmann <hausmann@kde.org>
  * Copyright (C) 2004, 2006, 2008, 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.
@@ skipping 35 matching lines @@
   ~HTMLIFrameElement() override;
   DOMTokenList* sandbox() const;
   DOMTokenList* allow() const;
 
   void SandboxValueWasSet();
   void AllowValueWasSet();
 
  private:
   explicit HTMLIFrameElement(Document&);
 
+  void SetCollapsed(bool) override;
+
   void ParseAttribute(const AttributeModificationParams&) override;
   bool IsPresentationAttribute(const QualifiedName&) const override;
   void CollectStyleForPresentationAttribute(const QualifiedName&,
                                             const AtomicString&,
                                             MutableStylePropertySet*) override;
 
   InsertionNotificationRequest InsertedInto(ContainerNode*) override;
   void RemovedFrom(ContainerNode*) override;
 
   bool LayoutObjectIsNeeded(const ComputedStyle&) override;
@@ skipping 15 matching lines @@
   AtomicString Csp() const override { return csp_; }
   const WebVector<WebFeaturePolicyFeature>& AllowedFeatures() const override {
     return allowed_features_;
   }
 
   AtomicString name_;
   AtomicString csp_;
   bool did_load_non_empty_document_;
   bool allow_fullscreen_;
   bool allow_payment_request_;
+  bool collapsed_by_client_;
   Member<HTMLIFrameElementSandbox> sandbox_;
   Member<HTMLIFrameElementAllow> allow_;
 
   WebVector<WebFeaturePolicyFeature> allowed_features_;
 
   ReferrerPolicy referrer_policy_;
 };
 
 }  // namespace blink
 
 #endif  // HTMLIFrameElement_h