[WIP] Keep matched preloads for a while

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 865 matching lines @@
   if (params.IsLinkPreload()) {
     resource->SetLinkPreload(true);
     return resource;
   }
 
   if (!IsReusableForPreloading(params, resource, false))
     return nullptr;
 
   resource->DecreasePreloadCount();
   preloads_.erase(it);
+  matched_preloads_.push_back(resource);
   return resource;
 }
 
 void ResourceFetcher::InsertAsPreloadIfNecessary(Resource* resource,
                                                  const FetchParameters& params,
                                                  Resource::Type type) {
   if (!params.IsSpeculativePreload() && !params.IsLinkPreload())
     return;
   // CSP layout tests verify that preloads are subject to access checks by
   // seeing if they are in the `preload started` list. Therefore do not add
@@ skipping 312 matching lines @@
   for (const auto& pair : preloads_) {
     Resource* resource = pair.value;
     if (policy == kClearAllPreloads || !resource->IsLinkPreload()) {
       resource->DecreasePreloadCount();
       if (resource->GetPreloadResult() == Resource::kPreloadNotReferenced)
         GetMemoryCache()->Remove(resource);
       keys_to_be_removed.push_back(pair.key);
     }
   }
   preloads_.RemoveAll(keys_to_be_removed);
+
+  matched_preloads_.clear();
 }
 
 void ResourceFetcher::WarnUnusedPreloads() {
   for (const auto& pair : preloads_) {
     Resource* resource = pair.value;
     if (resource && resource->IsLinkPreload() &&
         resource->GetPreloadResult() == Resource::kPreloadNotReferenced) {
       Context().AddConsoleMessage(
           "The resource " + resource->Url().GetString() +
               " was preloaded using link preload but not used within a few "
@@ skipping 406 matching lines @@
   RequestLoadStarted(resource->Identifier(), resource, params, kUse);
 }
 
 DEFINE_TRACE(ResourceFetcher) {
   visitor->Trace(context_);
   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