Implement chrome://view-http-cache with network service.

content/network/cache_url_loader.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_NETWORK_CACHE_URL_LOADER_H_
+#define CONTENT_NETWORK_CACHE_URL_LOADER_H_
+
+#include "content/common/url_loader.mojom.h"
+
+namespace net {
+class URLRequestContext;
+}
+
+namespace content {
+
+// Creates a URLLoader that responds to developer requests to view the cache.
+void StartCacheURLLoader(const ResourceRequest& request,
+                         net::URLRequestContext* request_context,
+                         mojom::URLLoaderClientPtr client);
+
+}  // namespace content
+
+#endif  // CONTENT_NETWORK_CACHE_URL_LOADER_H_