Validate generated MHTML in mhtml_generation_browsertest.cc tests.

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 1139 matching lines @@
               " was preloaded using link preload but not used within a few "
               "seconds from the window's load event. Please make sure it "
               "wasn't preloaded for nothing.",
           FetchContext::kLogWarningMessage);
     }
   }
 }
 
 ArchiveResource* ResourceFetcher::CreateArchive(Resource* resource) {
   // Only the top-frame can load MHTML.
-  if (!Context().IsMainFrame())
+  if (!Context().IsMainFrame()) {
+    Context().AddConsoleMessage(
+        "Attempted to load a multipart archive into an subframe: " +
+            resource->Url().GetString(),
+        FetchContext::kLogErrorMessage);
     return nullptr;
+  }
+
   archive_ = MHTMLArchive::Create(resource->Url(), resource->ResourceBuffer());
-  return archive_ ? archive_->MainResource() : nullptr;
+  if (!archive_) {
+    // Log if attempting to load an invalid archive resource.
+    Context().AddConsoleMessage(
+        "Malformed multipart archive: " + resource->Url().GetString(),
+        FetchContext::kLogErrorMessage);
+    return nullptr;
+  }
+
+  return archive_->MainResource();
 }
 
 ResourceTimingInfo* ResourceFetcher::GetNavigationTimingInfo() {
   return navigation_timing_info_.Get();
 }
 
 void ResourceFetcher::HandleLoadCompletion(Resource* resource) {
   Context().DidLoadResource(resource);
 
   resource->ReloadIfLoFiOrPlaceholderImage(this, Resource::kReloadIfNeeded);
@@ skipping 385 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