Add additional histogram events for prefetches to the prerender local

chrome/browser/prerender/prerender_local_predictor.cc

 // Copyright (c) 2012 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_local_predictor.h"
 
 #include <ctype.h>
 
 #include <algorithm>
 #include <map>
@@ skipping 1355 matching lines @@
       num_issued++;
       continue;
     }
   }
 }
 
 void PrerenderLocalPredictor::IssuePrerender(
     CandidatePrerenderInfo* info,
     LocalPredictorURLInfo* url_info) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
+  RecordEvent(EVENT_ISSUE_PRERENDER_CALLED);
   if (prefetch_list_->AddURL(url_info->url)) {
     RecordEvent(EVENT_PREFETCH_LIST_ADDED);
     // If we are prefetching rather than prerendering, now is the time to launch
     // the prefetch.
     if (IsLocalPredictorPrerenderPrefetchEnabled()) {
+      RecordEvent(EVENT_ISSUE_PRERENDER_PREFETCH_ENABLED);
       // Obtain the render frame host that caused this prefetch.
       RenderFrameHost* rfh = RenderFrameHost::FromID(info->render_process_id_,
                                                      info->render_frame_id_);
       // If it is still alive, launch the prefresh.
-      if (rfh)
+      if (rfh) {
         rfh->Send(new PrefetchMsg_Prefetch(rfh->GetRoutingID(), url_info->url));
+        RecordEvent(EVENT_ISSUE_PRERENDER_PREFETCH_ISSUED);
+      }
     }
   }
   PrerenderProperties* prerender_properties =
       GetIssuedPrerenderSlotForPriority(url_info->url, url_info->priority);
   if (!prerender_properties) {
     RecordEvent(EVENT_CONTINUE_PRERENDER_CHECK_PRIORITY_TOO_LOW);
     return;
   }
   RecordEvent(EVENT_CONTINUE_PRERENDER_CHECK_ISSUING_PRERENDER);
   DCHECK(prerender_properties != NULL);
@@ skipping 165 matching lines @@
       break;
     case content::SessionStorageNamespace::MERGE_RESULT_MERGEABLE:
       RecordEvent(EVENT_NAMESPACE_MISMATCH_MERGE_RESULT_MERGEABLE);
       break;
     default:
       NOTREACHED();
   }
 }
 
 }  // namespace prerender