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

content/browser/appcache/appcache_url_loader_job.cc

Index: content/browser/appcache/appcache_url_loader_job.cc
diff --git a/content/browser/appcache/appcache_url_loader_job.cc b/content/browser/appcache/appcache_url_loader_job.cc
index c6594d1595d35c3b0709549f105f02075c5c6c8a..1fad8cde980062f54592a0744ba32336ab18f7d9 100644
--- a/content/browser/appcache/appcache_url_loader_job.cc
+++ b/content/browser/appcache/appcache_url_loader_job.cc
@@ -75,7 +75,8 @@ void AppCacheURLLoaderJob::DeliverNetworkResponse() {
     // In network service land, if we are processing a navigation request, we
     // need to inform the loader callback that we are not going to handle this
     // request. The loader callback is valid only for navigation requests.
-    std::move(main_resource_loader_callback_).Run(StartLoaderCallback());
+    std::move(main_resource_loader_callback_)
+        .Run(StartLoaderCallback(), std::move(main_resource_fallback_handler_));
   } else {
     mojom::URLLoaderClientPtr client_ptr;
     network_loader_client_binding_.Bind(mojo::MakeRequest(&client_ptr));
@@ -223,16 +224,20 @@ void AppCacheURLLoaderJob::SetSubresourceLoadInfo(
   default_url_loader_factory_getter_ = default_url_loader;
 }
 
-void AppCacheURLLoaderJob::Start(mojom::URLLoaderRequest request,
-                                 mojom::URLLoaderClientPtr client) {
+void AppCacheURLLoaderJob::BindRequest(mojom::URLLoaderClientPtr client,
+                                       mojom::URLLoaderRequest request) {
   DCHECK(!binding_.is_bound());
   binding_.Bind(std::move(request));
 
+  client_ = std::move(client);
+
   binding_.set_connection_error_handler(base::Bind(
       &AppCacheURLLoaderJob::OnConnectionError, StaticAsWeakPtr(this)));
+}
 
-  client_ = std::move(client);
-
+void AppCacheURLLoaderJob::Start(mojom::URLLoaderRequest request,
+                                 mojom::URLLoaderClientPtr client) {
+  BindRequest(std::move(client), std::move(request));
   // Send the cached AppCacheResponse if any.
   if (info_.get())
     SendResponseInfo();
@@ -271,10 +276,12 @@ void AppCacheURLLoaderJob::OnResponseInfoLoaded(
     if (is_range_request())
       SetupRangeResponse();
 
-    if (IsResourceTypeFrame(request_.resource_type)) {
+    if (IsResourceTypeFrame(request_.resource_type) &&
+        main_resource_loader_callback_) {
       DCHECK(!main_resource_loader_callback_.is_null());
       std::move(main_resource_loader_callback_)
-          .Run(base::Bind(&AppCacheURLLoaderJob::Start, StaticAsWeakPtr(this)));
+          .Run(base::Bind(&AppCacheURLLoaderJob::Start, StaticAsWeakPtr(this)),
+               ResponseFallback());
     }
 
     response_body_stream_ = std::move(data_pipe_.producer_handle);