Make TaskManagerTabContentsResource explicitly handle prerendering and instant pages.

chrome/browser/prerender/prerender_manager.h

Index: chrome/browser/prerender/prerender_manager.h
diff --git a/chrome/browser/prerender/prerender_manager.h b/chrome/browser/prerender/prerender_manager.h
index 83dac141370c2c8f8012d147b7844ffecfc31ddd..806717015efb6188c06f4e7977f4f62c7918cb31 100644
--- a/chrome/browser/prerender/prerender_manager.h
+++ b/chrome/browser/prerender/prerender_manager.h
@@ -195,6 +195,9 @@ class PrerenderManager : public base::SupportsWeakPtr<PrerenderManager>,
   PrerenderContents* GetPrerenderContents(
       content::WebContents* web_contents) const;
 
+  // Returns a list of all WebContents being prerendered.
+  const std::vector<content::WebContents*> GetAllPrerenderingContents() const;
+
   // Maintaining and querying the set of WebContents belonging to this
   // PrerenderManager that are currently showing prerendered pages.
   void MarkWebContentsAsPrerendered(content::WebContents* web_contents,