predictors: Mark before_first_contentful_paint for resources fetched before fcp.

chrome/browser/predictors/resource_prefetch_predictor.cc

Index: chrome/browser/predictors/resource_prefetch_predictor.cc
diff --git a/chrome/browser/predictors/resource_prefetch_predictor.cc b/chrome/browser/predictors/resource_prefetch_predictor.cc
index ad3e824f5ea5adadb37ada20bb5fbf40412e3ae5..b26b7add827810a961b55b9b03348892d6b63380 100644
--- a/chrome/browser/predictors/resource_prefetch_predictor.cc
+++ b/chrome/browser/predictors/resource_prefetch_predictor.cc
@@ -417,6 +417,8 @@ void ResourcePrefetchPredictor::SetAllowPortInUrlsForTesting(bool state) {
 ResourcePrefetchPredictor::URLRequestSummary::URLRequestSummary()
     : resource_type(content::RESOURCE_TYPE_LAST_TYPE),
       priority(net::IDLE),
+      creation_time(base::TimeTicks()),
+      before_first_contentful_paint(false),
       was_cached(false),
       has_validators(false),
       always_revalidate(false) {}
@@ -427,6 +429,8 @@ ResourcePrefetchPredictor::URLRequestSummary::URLRequestSummary(
       resource_url(other.resource_url),
       resource_type(other.resource_type),
       priority(other.priority),
+      creation_time(other.creation_time),
+      before_first_contentful_paint(other.before_first_contentful_paint),
       mime_type(other.mime_type),
       was_cached(other.was_cached),
       redirect_url(other.redirect_url),
@@ -445,6 +449,7 @@ bool ResourcePrefetchPredictor::URLRequestSummary::SummarizeResponse(
   if (!request_info)
     return false;
 
+  summary->creation_time = request.creation_time();
   summary->resource_url = request.original_url();
   content::ResourceType resource_type_from_request =
       request_info->GetResourceType();
@@ -591,6 +596,22 @@ void ResourcePrefetchPredictor::RecordMainFrameLoadComplete(
   }
 }
 
+void ResourcePrefetchPredictor::RecordFirstContentfulPaint(
+    const NavigationID& navigation_id,
+    const base::TimeDelta& first_contentful_paint) {
+  NavigationMap::iterator nav_it =
+      inflight_navigations_.find(navigation_id);
+  if (nav_it == inflight_navigations_.end())
+    return;
+
+  base::TimeTicks fcp = nav_it->first.creation_time + first_contentful_paint;
+  for (auto& request_summary : nav_it->second->subresource_requests) {
+    request_summary.before_first_contentful_paint =
+        request_summary.creation_time < fcp;
+  }
+}
+
+
 void ResourcePrefetchPredictor::StartPrefetching(const GURL& url,
                                                  PrefetchOrigin origin) {
   TRACE_EVENT1("browser", "ResourcePrefetchPredictor::StartPrefetching", "url",
@@ -1179,6 +1200,8 @@ void ResourcePrefetchPredictor::LearnNavigation(
         continue;
 
       ResourceData* resource_to_add = data.add_resources();
+      resource_to_add->set_before_first_contentful_paint(
+          summary.before_first_contentful_paint);
       resource_to_add->set_resource_url(summary.resource_url.spec());
       resource_to_add->set_resource_type(
           static_cast<ResourceData::ResourceType>(summary.resource_type));