PlzNavigate: make MHTML iframe load working.

third_party/WebKit/Source/web/LocalFrameClientImpl.h

 /*
  * Copyright (C) 2009, 2012 Google Inc. All rights reserved.
  * Copyright (C) 2011 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
@@ skipping 210 matching lines @@
   void AbortClientNavigation() override;
 
   TextCheckerClient& GetTextCheckerClient() const override;
 
  private:
   explicit LocalFrameClientImpl(WebLocalFrameImpl*);
 
   bool IsLocalFrameClientImpl() const override { return true; }
   WebDevToolsAgentImpl* DevToolsAgent();
 
+  // An MHTML Archive is a set of resources, including iframes, that is parsed
+  // as a whole. This function tells whether of not an archive exists and should
+  // be used for loading a subframe.
+  bool IsLoadedAsMHTMLArchive() const;
+
   // The WebFrame that owns this object and manages its lifetime. Therefore,
   // the web frame object is guaranteed to exist.
   Member<WebLocalFrameImpl> web_frame_;
 
   String user_agent_;
 };
 
 DEFINE_TYPE_CASTS(LocalFrameClientImpl,
                   LocalFrameClient,
                   client,
                   client->IsLocalFrameClientImpl(),
                   client.IsLocalFrameClientImpl());
 
 }  // namespace blink
 
 #endif