Make PrerenderHandle an observer of PrerenderContents.

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 ed3f8ac92ad89517ab88b7a6018018a5d4ca4f7e..f5a75b9eaa96cde54f312e846812a35f3d0fbcbc 100644
--- a/chrome/browser/prerender/prerender_contents.h
+++ b/chrome/browser/prerender/prerender_contents.h
@@ -79,6 +79,10 @@ class PrerenderContents : public content::NotificationObserver,
     // Signals that the prerender has stopped running.
     virtual void OnPrerenderStop(PrerenderContents* contents) = 0;
 
+    // Signals the discovery, through redirects, of a new alias for this
+    // prerender.
+    virtual void OnPrerenderAddAlias(PrerenderContents* contents,
+                                     const GURL& alias_url);
    protected:

[mmenke, 2012/12/06 22:22:15]

nit:  Line break above protected

[gavinp, 2012/12/10 17:55:10]

Done.

     Observer();
     virtual ~Observer() = 0;
@@ -129,8 +133,10 @@ class PrerenderContents : public content::NotificationObserver,
   virtual ~PrerenderContents();
 
   // All observers of a PrerenderContents are removed after the OnPrerenderStop
-  // event is sent, so there is no need for a RemoveObserver() method.
+  // event is sent, so there is no need to call RemoveObserver() in the normal
+  // use case.
   void AddObserver(Observer* observer);
+  void RemoveObserver(Observer* observer);
 
   // For MatchComplete correctness, create a dummy replacement prerender
   // contents to stand in for this prerender contents that (which we are about
@@ -281,6 +287,7 @@ class PrerenderContents : public content::NotificationObserver,
   // These call out to methods on our Observers, using our observer_list_.
   void NotifyPrerenderStart();
   void NotifyPrerenderStop();
+  void NotifyPrerenderAddAlias(const GURL& alias_url);
 
   // Called whenever a RenderViewHost is created for prerendering.  Only called
   // once the RenderViewHost has a RenderView and RenderWidgetHostView.