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 8cd759ed453ca085e109421826162b766f3a553f..a1328c915bf59338177b0f36f87b64d1a82b1a70 100644
--- a/content/browser/appcache/appcache_url_loader_job.h
+++ b/content/browser/appcache/appcache_url_loader_job.h
@@ -111,6 +111,13 @@ 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;