Add support for fallback content for the frame. This includes main and subframes.

content/browser/appcache/appcache_url_loader_job.h

Index: content/browser/appcache/appcache_url_loader_job.h
diff --git a/content/browser/appcache/appcache_url_loader_job.h b/content/browser/appcache/appcache_url_loader_job.h
index d7ea502709cfebbcc07536d13c23b72f4c0cdc1b..96722f84586ec8dca4d25d960bdc0f64a854b0f7 100644
--- a/content/browser/appcache/appcache_url_loader_job.h
+++ b/content/browser/appcache/appcache_url_loader_job.h
@@ -112,6 +112,13 @@ class CONTENT_EXPORT AppCacheURLLoaderJob : public AppCacheJob,
     sub_resource_handler_ = std::move(handler);
   }
 
+  // Binds to the URLLoaderRequest instance passed in the |request| parameter.
+  // The URLLoaderClient instance is passed in the |client| parameter. This
+  // enables the client to receive notifications/data, etc for the ensuing
+  // URL load.
+  void BindRequest(mojom::URLLoaderClientPtr client,
+                  mojom::URLLoaderRequest request);
+
  protected:
   // AppCacheJob::Create() creates this instance.
   friend class AppCacheJob;