Add a stub implementation of the URLLoaderFactory for AppCache.

content/browser/appcache/appcache_url_loader_factory.cc

+// Copyright 2017 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_url_loader_factory.h"
+
+#include "base/bind.h"
+#include "base/logging.h"
+#include "content/browser/appcache/appcache_entry.h"
+#include "content/browser/appcache/appcache_policy.h"
+#include "content/browser/appcache/appcache_request.h"
+#include "content/browser/appcache/appcache_storage.h"
+#include "content/browser/appcache/chrome_appcache_service.h"
+#include "content/browser/url_loader_factory_getter.h"
+#include "content/common/network_service.mojom.h"
+#include "content/common/resource_request.h"
+#include "content/common/url_loader.mojom.h"
+#include "content/common/url_loader_factory.mojom.h"
+#include "content/public/browser/browser_thread.h"
+#include "mojo/public/cpp/bindings/associated_binding.h"
+#include "mojo/public/cpp/bindings/associated_interface_ptr.h"
+#include "mojo/public/cpp/bindings/binding_set.h"
+
+namespace content {
+
+namespace {
+
+// Handles AppCache URL loads for the network service.
+class AppCacheURLLoader : public AppCacheStorage::Delegate,
+                          public mojom::URLLoader {
+ public:
+  AppCacheURLLoader(const ResourceRequest& request,
+                    mojom::URLLoaderAssociatedRequest url_loader_request,
+                    int32_t routing_id,
+                    int32_t request_id,
+                    mojom::URLLoaderClientPtr client_info,
+                    ResourceType resource_type,
+                    ChromeAppCacheService* appcache_service,
+                    URLLoaderFactoryGetter* factory_getter)
+      : request_(request),
+        routing_id_(routing_id),
+        request_id_(request_id),
+        client_info_(std::move(client_info)),
+        resource_type_(resource_type),
+        appcache_service_(appcache_service),
+        factory_getter_(factory_getter),
+        binding_(this, std::move(url_loader_request)) {
+    binding_.set_connection_error_handler(base::Bind(
+        &AppCacheURLLoader::OnConnectionError, base::Unretained(this)));
+  }
+
+  ~AppCacheURLLoader() override {}
+
+  void Start() {
+    appcache_service_->storage()->FindResponseForMainRequest(request_.url,
+                                                             GURL(), this);
+  }
+
+  // mojom::URLLoader implementation:
+  void FollowRedirect() override {
+    network_loader_request_->FollowRedirect();
+  }
+
+  void SetPriority(net::RequestPriority priority,
+                   int32_t intra_priority_value) override {
+    DCHECK(false);
+  }
+
+ private:
+  // AppCacheStorage::Delegate methods
+  // The AppCacheNetworkServiceHandler instance is deleted on return from this

[kinuko, 2017/05/17 16:54:29]

The comment looks stale now

[ananta, 2017/05/17 18:14:08]

Done.

+  // function.
+  void OnMainResponseFound(const GURL& url,
+                           const AppCacheEntry& entry,
+                           const GURL& fallback_url,
+                           const AppCacheEntry& fallback_entry,
+                           int64_t cache_id,
+                           int64_t group_id,
+                           const GURL& manifest_url) override {
+    AppCachePolicy* policy = appcache_service_->appcache_policy();
+    bool was_blocked_by_policy =
+        !manifest_url.is_empty() && policy &&
+        !policy->CanLoadAppCache(manifest_url,
+                                 request_.first_party_for_cookies);
+
+    if (was_blocked_by_policy || !entry.has_response_id() ||
+        cache_id == kAppCacheNoCacheId) {
+      factory_getter_->GetNetworkFactory()->get()->CreateLoaderAndStart(
+          mojo::MakeRequest(&network_loader_request_), routing_id_, request_id_,

[jam, 2017/05/17 16:51:12]

I think you want to call Unbind() here and pass this on. or even, is there a
reason to bind the mojom::URLLoaderAssociatedRequest that came in to the
constructor, instead of holding on to it and passing it to the factories here
and below?

[ananta, 2017/05/17 18:14:08]

I ran into a number of problems trying to do that. This is a work in progress at
the moment.
Would it be reasonable to attempt that in a future patchset which should be
coming in soon.

[jam, 2017/05/18 14:16:14]

Which problems did you run into? I think we should try to fix them before this
lands, otherwise non-appcache requests will go through this class when URLLoader
interface is called.

[jam, 2017/05/19 00:03:50]

ok, nvm mind this comment for now, Ananta/Yuzhu/me met to discuss this and put a
summary in https://bugs.chromium.org/p/chromium/issues/detail?id=724323

+          mojom::kURLLoadOptionSendSSLInfo, request_, std::move(client_info_));
+    } else {
+      DLOG(WARNING) << "AppCache found for url " << url
+                    << " Returning AppCache factory\n";
+      // TODO(ananta)
+      // Provide the plumbing to initiate AppCache requests here.
+      factory_getter_->GetNetworkFactory()->get()->CreateLoaderAndStart(
+          mojo::MakeRequest(&network_loader_request_), routing_id_, request_id_,
+          mojom::kURLLoadOptionSendSSLInfo, request_, std::move(client_info_));
+    }
+  }
+
+  void OnConnectionError() { delete this; }
+
+  // The current request.
+  ResourceRequest request_;
+
+  // URLLoader proxy for the network service.
+  mojom::URLLoaderAssociatedPtr network_loader_request_;
+
+  // Routing id of the request. This is 0 for navigation requests. For
+  // subresource requests it is non zero.
+  int routing_id_;
+
+  // Request id.
+  int request_id_;
+
+  // The URLLoaderClient pointer. We call this interface with notifications
+  // about the URL load
+  mojom::URLLoaderClientPtr client_info_;
+
+  // Used to query AppCacheStorage to see if a request can be served out of the
+  /// AppCache.
+  scoped_refptr<ChromeAppCacheService> appcache_service_;
+
+  // Used to retrieve the network service factory to pass requests to the
+  // network service.
+  scoped_refptr<URLLoaderFactoryGetter> factory_getter_;
+
+  // Binds the URLLoaderClient with us.
+  mojo::AssociatedBinding<mojom::URLLoader> binding_;
+
+  DISALLOW_COPY_AND_ASSIGN(AppCacheURLLoader);
+};
+
+}  // namespace
+
+// Implements the URLLoaderFactory mojom for AppCache requests.
+AppCacheURLLoaderFactory::AppCacheURLLoaderFactory(
+    ChromeAppCacheService* appcache_service,
+    URLLoaderFactoryGetter* factory_getter)
+    : appcache_service_(appcache_service), factory_getter_(factory_getter) {}
+
+AppCacheURLLoaderFactory::~AppCacheURLLoaderFactory() {}
+
+// static
+void AppCacheURLLoaderFactory::CreateURLLoaderFactory(
+    mojom::URLLoaderFactoryRequest request,
+    ChromeAppCacheService* appcache_service,
+    URLLoaderFactoryGetter* factory_getter) {
+  std::unique_ptr<AppCacheURLLoaderFactory> factory_instance(
+      new AppCacheURLLoaderFactory(appcache_service, factory_getter));
+  AppCacheURLLoaderFactory* raw_factory = factory_instance.get();
+  raw_factory->loader_factory_bindings_.AddBinding(std::move(factory_instance),
+                                                   std::move(request));
+}
+
+void AppCacheURLLoaderFactory::CreateLoaderAndStart(
+    mojom::URLLoaderAssociatedRequest url_loader_request,
+    int32_t routing_id,
+    int32_t request_id,
+    uint32_t options,
+    const ResourceRequest& request,
+    mojom::URLLoaderClientPtr client) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  StartURLLoader(request, std::move(url_loader_request), routing_id, request_id,
+                 std::move(client));
+}
+
+void AppCacheURLLoaderFactory::SyncLoad(int32_t routing_id,
+                                        int32_t request_id,
+                                        const ResourceRequest& request,
+                                        SyncLoadCallback callback) {
+  NOTREACHED();
+}
+
+void AppCacheURLLoaderFactory::StartURLLoader(

[jam, 2017/05/17 16:51:12]

nit: what's the purpose of this separate method?

[ananta, 2017/05/17 18:14:08]

Thanks removed.

+    const ResourceRequest& request,
+    mojom::URLLoaderAssociatedRequest url_loader_request,
+    int32_t routing_id,
+    int32_t request_id,
+    mojom::URLLoaderClientPtr client_info) {
+  DCHECK_CURRENTLY_ON(BrowserThread::IO);
+  // This will get deleted when the connection is dropped by the client.

[kinuko, 2017/05/17 16:54:30]

It doesn't look using StrongBinding, is it true?

[ananta, 2017/05/17 18:14:08]

We delete the object in the connection error. Please see the AppCacheURLLoader
class above.

+  AppCacheURLLoader* loader = new AppCacheURLLoader(
+      request, std::move(url_loader_request), routing_id, request_id,
+      std::move(client_info), request.resource_type, appcache_service_.get(),
+      factory_getter_.get());
+  loader->Start();
+}
+
+}  // namespace content