Fix prerender histograms for multiple prerender case.

chrome/browser/prerender/prerender_local_predictor.cc

Index: chrome/browser/prerender/prerender_local_predictor.cc
diff --git a/chrome/browser/prerender/prerender_local_predictor.cc b/chrome/browser/prerender/prerender_local_predictor.cc
index 573ea62e7ea17770f900f87d844998e3702d2767..f9453d06188ff2f2d89bb10aabb995be75c81239 100644
--- a/chrome/browser/prerender/prerender_local_predictor.cc
+++ b/chrome/browser/prerender/prerender_local_predictor.cc
@@ -201,6 +201,7 @@ void PrerenderLocalPredictor::OnAddVisit(const history::BriefVisitInfo& info) {
       current_prerender_->url_id == info.url_id &&
       IsPrerenderStillValid(current_prerender_.get())) {
     prerender_manager_->histograms()->RecordLocalPredictorTimeUntilUsed(
+        ORIGIN_LOCAL_PREDICTOR,
         GetCurrentTime() - current_prerender_->actual_start_time,
         base::TimeDelta::FromMilliseconds(kMaxLocalPredictionTimeMs));
     last_swapped_in_prerender_.reset(current_prerender_.release());
@@ -372,15 +373,14 @@ void PrerenderLocalPredictor::OnPLTEventForURL(const GURL& url,
   if (IsPrerenderStillValid(prerender.get())) {
     base::TimeDelta prerender_age = GetCurrentTime() - prerender->start_time;
     prerender_manager_->histograms()->RecordSimulatedLocalBrowsingBaselinePLT(
-        page_load_time, url);
+        ORIGIN_LOCAL_PREDICTOR, page_load_time, url);
     if (prerender_age > page_load_time) {
       base::TimeDelta new_plt;
       if (prerender_age <  2 * page_load_time)
         new_plt = 2 * page_load_time - prerender_age;
       prerender_manager_->histograms()->RecordSimulatedLocalBrowsingPLT(
-          new_plt, url);
+          ORIGIN_LOCAL_PREDICTOR, new_plt, url);
     }
-
   }
 }