Treat responses with legacy LoFi headers as LoFi images.

third_party/WebKit/Source/core/loader/resource/ImageResource.cpp

Index: third_party/WebKit/Source/core/loader/resource/ImageResource.cpp
diff --git a/third_party/WebKit/Source/core/loader/resource/ImageResource.cpp b/third_party/WebKit/Source/core/loader/resource/ImageResource.cpp
index 2c2a733d6f44d40dac7a2b73a9bcf0a0c4d0e089..584eaf2d7b97709885e9de6338d1cfd33cb64096 100644
--- a/third_party/WebKit/Source/core/loader/resource/ImageResource.cpp
+++ b/third_party/WebKit/Source/core/loader/resource/ImageResource.cpp
@@ -461,8 +461,11 @@ bool ImageResource::ShouldReloadBrokenPlaceholder() const {
 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;