PlzNavigate: make MHTML iframe load working.

third_party/WebKit/Source/platform/loader/fetch/ResourceFetcher.cpp

 /*
     Copyright (C) 1998 Lars Knoll (knoll@mpi-hd.mpg.de)
     Copyright (C) 2001 Dirk Mueller (mueller@kde.org)
     Copyright (C) 2002 Waldo Bastian (bastian@kde.org)
     Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All
     rights reserved.
     Copyright (C) 2009 Torch Mobile Inc. http://www.torchmobile.com/
 
     This library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Library General Public
@@ skipping 395 matching lines @@
     response.SetTextEncodingName(substitute_data.TextEncoding());
   } else if (url.ProtocolIsData()) {
     data = NetworkUtils::ParseDataURLAndPopulateResponse(url, response);
     if (!data)
       return nullptr;
     // |response| is modified by parseDataURLAndPopulateResponse() and is
     // ready to be used.
   } else {
     ArchiveResource* archive_resource =
         archive_->SubresourceForURL(params.Url());
-    // Fall back to the network if the archive doesn't contain the resource.
+    // The archive doesn't contain the resource, the request must be aborted.
     if (!archive_resource)
       return nullptr;
     data = archive_resource->Data();
     response.SetURL(url);
     response.SetMimeType(archive_resource->MimeType());
     response.SetExpectedContentLength(data->size());
     response.SetTextEncodingName(archive_resource->TextEncoding());
   }
 
   Resource* resource = factory.Create(params.GetResourceRequest(),
@@ skipping 144 matching lines @@
   if (result == kBlock)
     return ResourceForBlockedRequest(params, factory, blocked_reason);
 
   if (!params.IsSpeculativePreload()) {
     // Only log if it's not for speculative preload.
     Context().RecordLoadingActivity(identifier, resource_request,
                                     factory.GetType(),
                                     params.Options().initiator_info.name);
   }
 
+  // An URL with the "cid" scheme can only be handled by an MHTML Archive.
+  // Abort the request when there is none.
+  if (resource_request.Url().ProtocolIs(kContentIdScheme) && !archive_) {

[pfeldman, 2017/05/05 20:45:36]

[perf]: check !archive_ first
[style nit]: drop {}

+    return nullptr;
+  }
+
   bool is_data_url = resource_request.Url().ProtocolIsData();
   bool is_static_data = is_data_url || substitute_data.IsValid() || archive_;
   if (is_static_data) {
     resource = ResourceForStaticData(params, factory, substitute_data);
     // Abort the request if the archive doesn't contain the resource, except in
     // the case of data URLs which might have resources such as fonts that need
-    // to be decoded only on demand.  These data URLs are allowed to be
+    // to be decoded only on demand. These data URLs are allowed to be
     // processed using the normal ResourceFetcher machinery.
     if (!resource && !is_data_url && archive_)
       return nullptr;
   }
   if (!resource) {
     resource =
         GetMemoryCache()->ResourceForURL(params.Url(), GetCacheIdentifier());
   }
 
   // If we got a preloaded resource from the cache for a non-preload request,
@@ skipping 929 matching lines @@
   visitor->Trace(context_);
   visitor->Trace(archive_);
   visitor->Trace(loaders_);
   visitor->Trace(non_blocking_loaders_);
   visitor->Trace(document_resources_);
   visitor->Trace(preloads_);
   visitor->Trace(resource_timing_info_map_);
 }
 
 }  // namespace blink