MHTML: Allows 'data:' URLs to be processed using normal request processing.

third_party/WebKit/Source/core/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
     License as published by the Free Software Foundation; either
@@ skipping 426 matching lines @@
             activityLogger = V8DOMActivityLogger::currentActivityLoggerIfIsolatedWorld();
 
         if (activityLogger) {
             Vector<String> argv;
             argv.append(Resource::resourceTypeToString(factory.type(), request.options().initiatorInfo));
             argv.append(request.url());
             activityLogger->logEvent("blinkRequestResource", argv.size(), argv.data());
         }
     }
 
-    bool isStaticData = request.resourceRequest().url().protocolIsData() || substituteData.isValid() || m_archive;
+    bool isDataUrl = request.resourceRequest().url().protocolIsData();
+    bool isStaticData = isDataUrl || substituteData.isValid() || m_archive;
     Resource* resource(nullptr);
     if (isStaticData) {
         resource = resourceForStaticData(request, factory, substituteData);
-        // Abort the request if the archive doesn't contain the resource.
-        if (!resource && m_archive)
+        // 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 processed using the normal ResourceFetcher machinery.
+        if (!resource && !isDataUrl && m_archive)
             return nullptr;
     }
     if (!resource)
         resource = memoryCache()->resourceForURL(request.url(), getCacheIdentifier());
 
     // See if we can use an existing resource from the cache. If so, we need to move it to be load blocking.
     moveCachedNonBlockingResourceToBlocking(resource, request);
 
     const RevalidationPolicy policy = determineRevalidationPolicy(factory.type(), request, resource, isStaticData);
     TRACE_EVENT_INSTANT1("blink", "ResourceFetcher::determineRevalidationPolicy", TRACE_EVENT_SCOPE_THREAD, "revalidationPolicy", policy);
@@ skipping 893 matching lines @@
     visitor->trace(m_context);
     visitor->trace(m_archive);
     visitor->trace(m_loaders);
     visitor->trace(m_nonBlockingLoaders);
     visitor->trace(m_documentResources);
     visitor->trace(m_preloads);
     visitor->trace(m_resourceTimingInfoMap);
 }
 
 } // namespace blink