Set "ping" requests priority as lowest

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 197 matching lines @@
       priority = kResourceLoadPriorityLow;
     } else if (speculative_preload_type ==
                    FetchParameters::SpeculativePreloadType::kInDocument &&
                image_fetched_) {
       // Speculative preload is used as a signal for scripts at the bottom of
       // the document.
       priority = kResourceLoadPriorityMedium;
     }
   } else if (FetchParameters::kLazyLoad == defer_option) {
     priority = kResourceLoadPriorityVeryLow;
+  } else if (resource_request.GetRequestContext() ==
+                 WebURLRequest::kRequestContextBeacon ||
+             resource_request.GetRequestContext() ==
+                 WebURLRequest::kRequestContextPing ||
+             resource_request.GetRequestContext() ==
+                 WebURLRequest::kRequestContextCSPReport) {
+    priority = kResourceLoadPriorityVeryLow;
   }
 
   // A manually set priority acts as a floor. This is used to ensure that
   // synchronous requests are always given the highest possible priority, as
   // well as to ensure that there isn't priority churn if images move in and out
   // of the viewport, or are displayed more than once, both in and out of the
   // viewport.
   return std::max(priority, resource_request.Priority());
 }
 
@@ skipping 1451 matching lines @@
   visitor->Trace(archive_);
   visitor->Trace(loaders_);
   visitor->Trace(non_blocking_loaders_);
   visitor->Trace(document_resources_);
   visitor->Trace(preloads_);
   visitor->Trace(matched_preloads_);
   visitor->Trace(resource_timing_info_map_);
 }
 
 }  // namespace blink