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 8ddd92a49dededf1527e9d065f0f3d539f28e15f..5155d31ce44b006398924c8a3d0fe69011a8aa4b 100644
--- a/content/browser/appcache/appcache_url_loader_job.cc
+++ b/content/browser/appcache/appcache_url_loader_job.cc
@@ -224,16 +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();
@@ -272,7 +276,7 @@ void AppCacheURLLoaderJob::OnResponseInfoLoaded(
     if (is_range_request())
       SetupRangeResponse();
 
-    if (IsResourceTypeFrame(request_.resource_type)) {
+    if (IsResourceTypeFrame(request_.resource_type) && !client_) {

[michaeln, 2017/07/26 23:08:41]

i don't understand the purpose of the !client_ check and why that affects
whether we could invoke the loader_callback?

[ananta, 2017/07/27 02:40:25]

For fallback responses the callback would be null. I changed the check to
validate
if the callback is valid.

       DCHECK(!main_resource_loader_callback_.is_null());
       std::move(main_resource_loader_callback_)
           .Run(base::Bind(&AppCacheURLLoaderJob::Start, StaticAsWeakPtr(this)));
@@ -429,9 +433,9 @@ void AppCacheURLLoaderJob::NotifyCompleted(int error_code) {
   if (storage_.get())
     storage_->CancelDelegateCallbacks(this);
 
-  const net::HttpResponseInfo* http_info = is_range_request()
-                                               ? range_response_info_.get()
-                                               : info_->http_response_info();
+  const net::HttpResponseInfo* http_info =
+      is_range_request() ? range_response_info_.get()
+                         : (info_ ? info_->http_response_info() : nullptr);
 
   ResourceRequestCompletionStatus request_complete_data;
   request_complete_data.error_code = error_code;
@@ -444,7 +448,7 @@ void AppCacheURLLoaderJob::NotifyCompleted(int error_code) {
     request_complete_data.completion_time = base::TimeTicks::Now();
     request_complete_data.encoded_body_length =
         is_range_request() ? range_response_info_->headers->GetContentLength()
-                           : info_->response_data_size();
+                           : (info_ ? info_->response_data_size() : 0);
     request_complete_data.decoded_body_length =
         request_complete_data.encoded_body_length;
   }