Add PrerenderStatusEvent on Prerenders

chrome/browser/prerender/prerender_contents.h

Index: chrome/browser/prerender/prerender_contents.h
diff --git a/chrome/browser/prerender/prerender_contents.h b/chrome/browser/prerender/prerender_contents.h
index 4a46b49037a69bb3ca4f7f445b02dc898c41a748..f8a9fb7062bb1cdf492e262f1cda919b4def461e 100644
--- a/chrome/browser/prerender/prerender_contents.h
+++ b/chrome/browser/prerender/prerender_contents.h
@@ -117,6 +117,7 @@ class PrerenderContents : public content::NotificationObserver,
   // page should be part of.
   virtual void StartPrerendering(
       int creator_child_id,
+      int prerender_id,
       const gfx::Size& size,
       content::SessionStorageNamespace* session_storage_namespace,
       bool is_control_group);
@@ -394,6 +395,9 @@ class PrerenderContents : public content::NotificationObserver,
   // The process that created the child id.
   int creator_child_id_;
 
+  // The prerender id from the launcher.
+  int prerender_id_;
+
   // The size of the WebView from the launching page.
   gfx::Size size_;