[Prerender] first contentful paint histograms.

chrome/browser/page_load_metrics/page_load_tracker.cc

Index: chrome/browser/page_load_metrics/page_load_tracker.cc
diff --git a/chrome/browser/page_load_metrics/page_load_tracker.cc b/chrome/browser/page_load_metrics/page_load_tracker.cc
index 83888d86e7dd5c9706fa2bfd02589ea0905b1c44..6c1b4a7263ba7f369aa4b0a1892482e8e1efe03d 100644
--- a/chrome/browser/page_load_metrics/page_load_tracker.cc
+++ b/chrome/browser/page_load_metrics/page_load_tracker.cc
@@ -305,15 +305,6 @@ PageLoadTracker::PageLoadTracker(
       aborted_chain_size_same_url_(aborted_chain_size_same_url),
       embedder_interface_(embedder_interface) {
   DCHECK(!navigation_handle->HasCommitted());
-  if (embedder_interface_->IsPrerendering(
-          navigation_handle->GetWebContents())) {
-    DCHECK(!started_in_foreground_);
-    // For the time being, we do not track prerenders. See crbug.com/648338 for
-    // details.
-    StopTracking();
-    return;
-  }
-
   embedder_interface_->RegisterObservers(this);
   INVOKE_AND_PRUNE_OBSERVERS(observers_, OnStart, navigation_handle,
                              currently_committed_url, started_in_foreground_);