Add recording of when a prerender actually starts to prerender histograms.

chrome/browser/prerender/prerender_histograms.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/prerender/prerender_histograms.h"
 
 #include <string>
 
 #include "base/metrics/field_trial.h"
 #include "base/metrics/histogram.h"
@@ skipping 135 matching lines @@
 
   last_origin_ = origin;
   last_experiment_id_ = experiment;
 
   // If we observe multiple tags within the 30 second window, we will still
   // reset the window to begin at the most recent occurrence, so that we will
   // always be in a window in the 30 seconds from each occurrence.
   last_prerender_seen_time_ = GetCurrentTimeTicks();
   seen_any_pageload_ = false;
   seen_pageload_started_after_prerender_ = false;
+}
 
+void PrerenderHistograms::RecordPrerenderStarted(Origin origin) const {
   if (OriginIsOmnibox(origin)) {
     UMA_HISTOGRAM_COUNTS("Prerender.OmniboxPrerenderCount_" +
                          GetOmniboxHistogramSuffix(), 1);
   }
 }
 
 void PrerenderHistograms::RecordUsedPrerender(Origin origin) const {
   if (OriginIsOmnibox(origin)) {
     UMA_HISTOGRAM_COUNTS("Prerender.OmniboxNavigationsUsedPrerenderCount_" +
                          GetOmniboxHistogramSuffix(), 1);
@@ skipping 124 matching lines @@
   return last_origin_;
 }
 
 bool PrerenderHistograms::IsOriginExperimentWash() const {
   if (!WithinWindow())
     return false;
   return origin_experiment_wash_;
 }
 
 }  // namespace prerender