PlzNavigate: make MHTML iframe load working.

third_party/WebKit/public/web/WebFrameClient.h

Index: third_party/WebKit/public/web/WebFrameClient.h
diff --git a/third_party/WebKit/public/web/WebFrameClient.h b/third_party/WebKit/public/web/WebFrameClient.h
index cd405beba518b932d17bed0f42509b86d00a3f66..ae5b41c0d9319868be3ca65bc71f8483c5c586ab 100644
--- a/third_party/WebKit/public/web/WebFrameClient.h
+++ b/third_party/WebKit/public/web/WebFrameClient.h
@@ -319,6 +319,11 @@ class BLINK_EXPORT WebFrameClient {
     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),
@@ -329,7 +334,8 @@ class BLINK_EXPORT WebFrameClient {
           is_client_redirect(false),
           is_cache_disabled(false),
           should_check_main_world_content_security_policy(
-              kWebContentSecurityPolicyDispositionCheck) {}
+              kWebContentSecurityPolicyDispositionCheck),
+          archive_status(ArchiveStatus::Absent) {}
   };
 
   virtual WebNavigationPolicy DecidePolicyForNavigation(