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

content/common/network_service.mojom

Index: content/common/network_service.mojom
diff --git a/content/common/network_service.mojom b/content/common/network_service.mojom
new file mode 100644
index 0000000000000000000000000000000000000000..4067316da76898a2cda86ae1113f904270d788a2
--- /dev/null
+++ b/content/common/network_service.mojom
@@ -0,0 +1,13 @@
+// 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.
+
+module content.mojom;
+
+import "url_loader.mojom";
+
+// Browser interface to the network service.
+interface NetworkService {
+  HandleViewCacheRequest(URLRequest request,
+                         URLLoaderClient client);
+};