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

content/browser/appcache/appcache_request_handler.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/appcache/appcache_request_handler.h"
 
 #include <utility>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 284 matching lines @@
   DCHECK(entry.has_response_id());
 
   // Cache information about the response, for use by GetExtraResponseInfo.
   cache_id_ = cache_id;
   manifest_url_ = manifest_url;
 
   if (IsResourceTypeFrame(resource_type_) && !namespace_entry_url.is_empty())
     host_->NotifyMainResourceIsNamespaceEntry(namespace_entry_url);
 
   job_->DeliverAppCachedResponse(manifest_url, cache_id, entry, is_fallback);
+  // In the network service world, we need to release the AppCacheJob instance
+  // created  for handling navigation requests. These instances will get

[kinuko, 2017/07/28 09:50:28]

nit: extra space

[ananta, 2017/07/28 22:59:22]

Done.

+  // destroyed when the client disconnects.
+  navigation_request_job_.release();
 }
 
 void AppCacheRequestHandler::DeliverErrorResponse() {
   DCHECK(job_.get() && job_->IsWaiting());
   DCHECK_EQ(kAppCacheNoCacheId, cache_id_);
   DCHECK(manifest_url_.is_empty());
   job_->DeliverErrorResponse();
+  // In the network service world, we need to release the AppCacheJob instance
+  // created  for handling navigation requests. These instances will get

[kinuko, 2017/07/28 09:50:28]

ditto

[ananta, 2017/07/28 22:59:22]

Done.

+  // destroyed when the client disconnects.
+  navigation_request_job_.release();
 }
 
 void AppCacheRequestHandler::DeliverNetworkResponse() {
   DCHECK(job_.get() && job_->IsWaiting());
   DCHECK_EQ(kAppCacheNoCacheId, cache_id_);
   DCHECK(manifest_url_.is_empty());
   job_->DeliverNetworkResponse();
+
+  // In the network service world, we need to destroy the AppCacheJob instance
+  // created  for handling navigation requests.

[kinuko, 2017/07/28 09:50:28]

ditto

[ananta, 2017/07/28 22:59:22]

Done.

+  navigation_request_job_.reset(nullptr);
 }
 
 void AppCacheRequestHandler::OnPrepareToRestart() {
   DCHECK(job_->IsDeliveringNetworkResponse() || job_->IsCacheEntryNotFound());
 
   // Any information about the source of the response is no longer relevant.
   cache_id_ = kAppCacheNoCacheId;
   manifest_url_ = GURL();
 
   cache_entry_not_found_ = job_->IsCacheEntryNotFound();
@@ skipping 18 matching lines @@
     loader_job->SetSubresourceLoadInfo(
         std::move(subresource_load_info_),
         network_url_loader_factory_getter_.get());
   }
 
   return job;
 }
 
 std::unique_ptr<AppCacheJob> AppCacheRequestHandler::MaybeCreateJobForFallback(
     net::NetworkDelegate* network_delegate) {
-  if (!base::FeatureList::IsEnabled(features::kNetworkService))
+  if (!base::FeatureList::IsEnabled(features::kNetworkService) ||
+      IsMainResourceType(resource_type_)) {
     return CreateJob(network_delegate);
+  }
   // In network service land, the job initiates a fallback request. We reuse
   // the existing job to deliver the fallback response.

[kinuko, 2017/07/28 09:50:28]

This comment doesn't explain why we have IsMainResourceType above, can you
update the comment?

   DCHECK(job_.get());
   return std::unique_ptr<AppCacheJob>(job_.get());
 }
 
 // Main-resource handling ----------------------------------------------
 
 std::unique_ptr<AppCacheJob> AppCacheRequestHandler::MaybeLoadMainResource(
     net::NetworkDelegate* network_delegate) {
   DCHECK(!job_.get());
   DCHECK(host_);
@@ skipping 202 matching lines @@
     const ResourceRequest& resource_request,
     ResourceContext* resource_context,
     LoaderCallback callback) {
   // MaybeLoadMainResource will invoke navigation_request_job's methods
   // asynchronously via AppCacheStorage::Delegate.
   navigation_request_job_ = MaybeLoadMainResource(nullptr);
   if (!navigation_request_job_.get()) {
     std::move(callback).Run(StartLoaderCallback());
     return;
   }
+  // The AppCacheJob for the navigation request will get destroyed when the
+  // client connection is dropped.

[michaeln, 2017/07/28 19:11:02]

the lifetime is explained well enough in other comments, not sure this one is
needed

[ananta, 2017/07/28 22:59:22]

Thanks. Removed

   navigation_request_job_->AsURLLoaderJob()->set_main_resource_loader_callback(
       std::move(callback));
 }
 
 mojom::URLLoaderFactoryPtr
 AppCacheRequestHandler::MaybeCreateSubresourceFactory() {
   mojom::URLLoaderFactoryPtr factory_ptr = nullptr;
 
   // The factory is destroyed when the renderer drops the connection.
   AppCacheSubresourceURLFactory::CreateURLLoaderFactory(
       network_url_loader_factory_getter_.get(), appcache_host_, &factory_ptr);
 
   return factory_ptr;
 }
 
+bool AppCacheRequestHandler::MaybeCreateLoaderForResponse(
+    const ResourceResponseHead& response,
+    mojom::URLLoaderPtr* loader,
+    mojom::URLLoaderClientRequest* client_request) {
+  request_->AsURLLoaderRequest()->set_response(response);
+  // The AppCacheJob will get destroyed when the client connection is
+  // dropped.
+  AppCacheJob* job = MaybeLoadFallbackForResponse(nullptr);
+  if (job) {
+    mojom::URLLoaderClientPtr client;
+    *client_request = mojo::MakeRequest(&client);
+    mojom::URLLoaderRequest loader_request = mojo::MakeRequest(loader);
+
+    job->AsURLLoaderJob()->BindRequest(std::move(client),
+                                       std::move(loader_request));
+    return true;
+  }
+  return false;
+}
+
 }  // namespace content