base::Bind: Implement a 1-arity CancelableCallback and use this to implement

chrome/browser/renderer_host/offline_resource_handler.h

Index: chrome/browser/renderer_host/offline_resource_handler.h
diff --git a/chrome/browser/renderer_host/offline_resource_handler.h b/chrome/browser/renderer_host/offline_resource_handler.h
index b28d5f78d8da35b8c7475cb828af922bb1e176b3..bebb24ac6b6778fbc7457f17d63bcc08f3533880 100644
--- a/chrome/browser/renderer_host/offline_resource_handler.h
+++ b/chrome/browser/renderer_host/offline_resource_handler.h
@@ -52,7 +52,7 @@ class OfflineResourceHandler : public ResourceHandler {
   void OnBlockingPageComplete(bool proceed);
 
  private:
-  // Erase the state assocaited with a deferred load request.
+  // Erase the state associated with a deferred load request.
   void ClearRequestInfo();
   bool IsRemote(const GURL& url) const;
 
@@ -80,8 +80,7 @@ class OfflineResourceHandler : public ResourceHandler {
   int deferred_request_id_;
   GURL deferred_url_;
 
-  scoped_refptr<net::CancelableOldCompletionCallback<OfflineResourceHandler> >
-      appcache_completion_callback_;
+  net::CancelableCompletionCallback appcache_completion_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(OfflineResourceHandler);
 };