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 d07ce926d7f260dc8c0efb9659fe41a188fd6be0..d1826afadf8788a904252141e8ecc842d7689312 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.response()
-        .httpHeaderField("chrome-proxy-content-transform")
-        .contains("empty-image");
+               .httpHeaderField("chrome-proxy-content-transform")
+               .contains("empty-image") ||
+           resource.response()
+               .httpHeaderField("chrome-proxy")
+               .contains("q=low");
   }
   return resource.resourceRequest().previewsState() &
          WebURLRequest::ServerLoFiOn;