Add support in the network service for different contexts.

content/browser/url_loader_factory_getter.h

+// 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.
+
+#ifndef CONTENT_BROWSER_URL_LOADER_FACTORY_GETTER_H_
+#define CONTENT_BROWSER_URL_LOADER_FACTORY_GETTER_H_
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "content/common/content_export.h"
+#include "content/common/url_loader_factory.mojom.h"
+#include "content/public/browser/browser_thread.h"
+
+namespace content {
+
+// Holds on to URLLoaderFactory for a given StoragePartition allows code running

[scottmg, 2017/05/16 03:53:43]

"for a given StoragePartition allows code" missing "and" in there.

[jam, 2017/05/16 04:08:50]

Done.

+// on the IO thread to access them. Note these are the factories used by the
+// browser process for frame requests.
+class CONTENT_EXPORT URLLoaderFactoryGetter
+    : public base::RefCountedThreadSafe<URLLoaderFactoryGetter,
+                                        BrowserThread::DeleteOnIOThread> {
+ public:
+  URLLoaderFactoryGetter();
+  ~URLLoaderFactoryGetter();
+
+  // Initializes this object on the UI thread.
+  void Initialize(mojom::URLLoaderFactoryPtr network_factory);
+
+  // Called on the IO thread to get the URLLoaderFactory to the network service.
+  // The pointer shouldn't be cached.
+  mojom::URLLoaderFactoryPtr* GetNetworkFactory();
+
+  // Overrides the network URLLoaderFactory for subsequent requests. Passing a
+  // null pointer will restore the default behavior.
+  // This is called on the UI thread.
+  void SetNetworkFactoryForTesting(mojom::URLLoaderFactoryPtr test_factory);
+
+ private:
+  friend struct BrowserThread::DeleteOnThread<BrowserThread::IO>;
+
+  void InitializeOnIOThread(mojom::URLLoaderFactoryPtrInfo network_factory);
+  void SetTestNetworkFactoryOnIOThread(
+      mojom::URLLoaderFactoryPtrInfo test_factory);
+
+  // Only accessed on IO thread.
+  mojom::URLLoaderFactoryPtr network_factory_;
+  mojom::URLLoaderFactoryPtr test_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(URLLoaderFactoryGetter);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_URL_LOADER_FACTORY_GETTER_H_