Treat responses with legacy LoFi headers as LoFi images.

third_party/WebKit/Source/core/loader/resource/ImageResource.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) 2006 Samuel Weinig (sam.weinig@gmail.com)
     Copyright (C) 2004, 2005, 2006, 2007 Apple Inc. All rights reserved.
 
     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 443 matching lines @@
     case PlaceholderOption::kDoNotReloadPlaceholder:
       return false;
   }
   NOTREACHED();
   return false;
 }
 
 static bool IsLoFiImage(const ImageResource& resource) {
   if (resource.IsLoaded()) {
     return resource.GetResponse()
-        .HttpHeaderField("chrome-proxy-content-transform")
-        .Contains("empty-image");
+               .HttpHeaderField("chrome-proxy-content-transform")
+               .Contains("empty-image") ||
+           resource.GetResponse()
+               .HttpHeaderField("chrome-proxy")
+               .Contains("q=low");
   }
   return resource.GetResourceRequest().GetPreviewsState() &
          WebURLRequest::kServerLoFiOn;
 }
 
 void ImageResource::ReloadIfLoFiOrPlaceholderImage(
     ResourceFetcher* fetcher,
     ReloadLoFiOrPlaceholderPolicy policy) {
   if (policy == kReloadIfNeeded && !ShouldReloadBrokenPlaceholder())
     return;
@@ skipping 115 matching lines @@
     //    reloading in Step 3 due to notifyObservers()'s
     //    schedulingReloadOrShouldReloadBrokenPlaceholder() check.
     // 3. reloadIfLoFiOrPlaceholderImage() is called via ResourceFetcher
     //    (a) via didFinishLoading() called in decodeError(), or
     //    (b) after returning ImageResource::updateImage().
     DecodeError(all_data_received);
   }
 }
 
 }  // namespace blink