Revert of Revert of Add Mojo interfaces for out-of-process proxy resolver.

net/interfaces/BUILD.gn

Index: net/interfaces/BUILD.gn
diff --git a/net/interfaces/BUILD.gn b/net/interfaces/BUILD.gn
new file mode 100644
index 0000000000000000000000000000000000000000..03a07785251e4d2fa222319e0a4cab1d0c4c5f9a
--- /dev/null
+++ b/net/interfaces/BUILD.gn
@@ -0,0 +1,12 @@
+# Copyright 2015 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.
+
+import("//third_party/mojo/src/mojo/public/tools/bindings/mojom.gni")
+
+mojom("interfaces") {
+  sources = [
+    "host_resolver_service.mojom",
+    "proxy_resolver_service.mojom",
+  ]
+}