Add observer interface to PrerenderContents.

chrome/browser/prerender/prerender_manager.cc

Index: chrome/browser/prerender/prerender_manager.cc
diff --git a/chrome/browser/prerender/prerender_manager.cc b/chrome/browser/prerender/prerender_manager.cc
index 4adfca282a57de6265e725bd2b02003ecb4798c8..d8666ccaee450f8795a1cb2085507d42e9863ed9 100644
--- a/chrome/browser/prerender/prerender_manager.cc
+++ b/chrome/browser/prerender/prerender_manager.cc
@@ -1053,6 +1053,7 @@ PrerenderHandle* PrerenderManager::AddPrerender(
                         GetExpiryTimeForNewPrerender()));
   if (!prerender_contents->Init())
     return NULL;
+  prerender_tracker_->AddPrerenderContents(prerender_contents);
 
   histograms_->RecordPrerenderStarted(origin);
   DCHECK(!prerender_contents->prerendering_has_started());
@@ -1168,7 +1169,7 @@ PrerenderContents* PrerenderManager::CreatePrerenderContents(
     uint8 experiment_id) {
   DCHECK(CalledOnValidThread());
   return prerender_contents_factory_->CreatePrerenderContents(
-      this, prerender_tracker_, profile_, url, referrer, origin, experiment_id);
+      this, profile_, url, referrer, origin, experiment_id);
 }
 
 void PrerenderManager::SortActivePrerenders() {