PlzNavigate: make MHTML iframe load working.

third_party/WebKit/public/web/WebFrameClient.h

 /*
  * Copyright (C) 2011, 2012 Google 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.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 301 matching lines @@
     WebNavigationPolicy default_policy;
     bool replaces_current_history_item;
     bool is_history_navigation_in_new_child_frame;
     bool is_client_redirect;
     WebFormElement form;
     bool is_cache_disabled;
     WebSourceLocation source_location;
     WebContentSecurityPolicyDisposition
         should_check_main_world_content_security_policy;
 
+    // Specify whether or not a MHTML Archive can be used to load a subframe
+    // resource instead of doing a network request.
+    enum class ArchiveStatus { Absent, Present };
+    ArchiveStatus archive_status;
+
     NavigationPolicyInfo(WebURLRequest& url_request)
         : extra_data(nullptr),
           url_request(url_request),
           navigation_type(kWebNavigationTypeOther),
           default_policy(kWebNavigationPolicyIgnore),
           replaces_current_history_item(false),
           is_history_navigation_in_new_child_frame(false),
           is_client_redirect(false),
           is_cache_disabled(false),
           should_check_main_world_content_security_policy(
-              kWebContentSecurityPolicyDispositionCheck) {}
+              kWebContentSecurityPolicyDispositionCheck),
+          archive_status(ArchiveStatus::Absent) {}
   };
 
   virtual WebNavigationPolicy DecidePolicyForNavigation(
       const NavigationPolicyInfo& info) {
     return info.default_policy;
   }
 
   // During a history navigation, we may choose to load new subframes from
   // history as well.  This returns such a history item if appropriate.
   virtual WebHistoryItem HistoryItemForNewChildFrame() {
@@ skipping 434 matching lines @@
   // Overwrites the given URL to use an HTML5 embed if possible.
   // An empty URL is returned if the URL is not overriden.
   virtual WebURL OverrideFlashEmbedWithHTML(const WebURL& url) {
     return WebURL();
   }
 };
 
 }  // namespace blink
 
 #endif