fix: create system network context for global requests

Global requests currently includes DNS over HTTPS requests,
certain cert validation requests (OCSP, AIA, etc) on some platforms
and geolocation requests.

atom/browser/net/system_network_context_manager.h

@@ -0,0 +1,101 @@
+// Copyright (c) 2018 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#ifndef ATOM_BROWSER_NET_SYSTEM_NETWORK_CONTEXT_MANAGER_H_
+#define ATOM_BROWSER_NET_SYSTEM_NETWORK_CONTEXT_MANAGER_H_
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/optional.h"
+#include "chrome/browser/net/proxy_config_monitor.h"
+#include "services/network/public/mojom/network_context.mojom.h"
+#include "services/network/public/mojom/network_service.mojom.h"
+
+namespace network {
+namespace mojom {
+class URLLoaderFactory;
+}
+class SharedURLLoaderFactory;
+}  // namespace network
+
+// Responsible for creating and managing access to the system NetworkContext.
+// Lives on the UI thread. The NetworkContext this owns is intended for requests
+// not associated with a session. It stores no data on disk, and has no HTTP
+// cache, but it does have ephemeral cookie and channel ID stores.
+//
+// This class is also responsible for configuring global NetworkService state.
+//
+// The "system" NetworkContext will either share a URLRequestContext with
+// IOThread's SystemURLRequestContext and be part of IOThread's NetworkService
+// (If the network service is disabled) or be an independent NetworkContext
+// using the actual network service.
+class SystemNetworkContextManager {
+ public:
+  SystemNetworkContextManager();
+  ~SystemNetworkContextManager();
+
+  // Returns default set of parameters for configuring the network service.
+  static network::mojom::NetworkContextParamsPtr
+  CreateDefaultNetworkContextParams();
+
+  // Initializes |network_context_params| as needed to set up a system
+  // NetworkContext. If the network service is disabled,
+  // |network_context_request| will be for the NetworkContext used by the
+  // SystemNetworkContextManager. Otherwise, this method can still be used to
+  // help set up the IOThread's in-process URLRequestContext.
+  //
+  // Must be called before the system NetworkContext is first used.
+  void SetUp(network::mojom::NetworkContextRequest* network_context_request,
+             network::mojom::NetworkContextParamsPtr* network_context_params);
+
+  // Returns the System NetworkContext. May only be called after SetUp(). Does
+  // any initialization of the NetworkService that may be needed when first
+  // called.
+  network::mojom::NetworkContext* GetContext();
+
+  // Returns a URLLoaderFactory owned by the SystemNetworkContextManager that is
+  // backed by the SystemNetworkContext. Allows sharing of the URLLoaderFactory.
+  // Prefer this to creating a new one.  Call Clone() on the value returned by
+  // this method to get a URLLoaderFactory that can be used on other threads.
+  network::mojom::URLLoaderFactory* GetURLLoaderFactory();
+
+  // Returns a SharedURLLoaderFactory owned by the SystemNetworkContextManager
+  // that is backed by the SystemNetworkContext.
+  scoped_refptr<network::SharedURLLoaderFactory> GetSharedURLLoaderFactory();
+
+  // Called when content creates a NetworkService. Creates the
+  // SystemNetworkContext, if the network service is enabled.
+  void OnNetworkServiceCreated(network::mojom::NetworkService* network_service);
+
+ private:
+  class URLLoaderFactoryForSystem;
+
+  // Creates parameters for the NetworkContext. May only be called once, since
+  // it initializes some class members.
+  network::mojom::NetworkContextParamsPtr CreateNetworkContextParams();
+
+  ProxyConfigMonitor proxy_config_monitor_;
+
+  // NetworkContext using the network service, if the network service is
+  // enabled. nullptr, otherwise.
+  network::mojom::NetworkContextPtr network_service_network_context_;
+
+  // This is a NetworkContext that wraps the IOThread's SystemURLRequestContext.
+  // Always initialized in SetUp, but it's only returned by Context() when the
+  // network service is disabled.
+  network::mojom::NetworkContextPtr io_thread_network_context_;
+
+  // URLLoaderFactory backed by the NetworkContext returned by GetContext(), so
+  // consumers don't all need to create their own factory.
+  scoped_refptr<URLLoaderFactoryForSystem> shared_url_loader_factory_;
+  network::mojom::URLLoaderFactoryPtr url_loader_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(SystemNetworkContextManager);
+};
+
+#endif  // ATOM_BROWSER_NET_SYSTEM_NETWORK_CONTEXT_MANAGER_H_