Fix memory leak in PrerenderDispatcher.

chrome/renderer/prerender/prerender_dispatcher.h

Index: chrome/renderer/prerender/prerender_dispatcher.h
diff --git a/chrome/renderer/prerender/prerender_dispatcher.h b/chrome/renderer/prerender/prerender_dispatcher.h
index 5537401112cb13637d6849b91f2c780a153c335d..3ee2b7f3217cb3edea22dd9f79ed2ee9d8ab89b6 100644
--- a/chrome/renderer/prerender/prerender_dispatcher.h
+++ b/chrome/renderer/prerender/prerender_dispatcher.h
@@ -9,15 +9,20 @@
 #include <map>
 
 #include "base/compiler_specific.h"
+#include "base/memory/scoped_ptr.h"
 #include "content/public/renderer/render_process_observer.h"
 
 class GURL;
 
 namespace prerender {
 
+class PrerenderingSupport;
+
 // PrerenderDispatcher keeps track of which URLs are being prerendered. There
 // is only one PrerenderDispatcher per render process, and it will only be
-// aware of prerenders that are triggered by this render process.
+// aware of prerenders that are triggered by this render process.  As well,
+// it holds on to other objects that must exist once per-renderer process,
+// such as the PrerenderingSupport.
 class PrerenderDispatcher : public content::RenderProcessObserver {
  public:
   PrerenderDispatcher();
@@ -34,6 +39,10 @@ class PrerenderDispatcher : public content::RenderProcessObserver {
 
   typedef std::map<GURL, int> PrerenderMap;
   PrerenderMap prerender_urls_;
+
+  // There is one PrerenderingSupport object per renderer, and it provides
+  // the interface to prerendering to the WebKit platform.
+  scoped_ptr<PrerenderingSupport> prerendering_support_;
 };
 
 }  // namespace prerender