[headless] Refactor headless devtools client API.

headless/lib/browser/devtools_api/deprecated_domain_h.template

Index: headless/lib/browser/devtools_api/deprecated_domain_h.template
diff --git a/cc/ipc/frame_sink_id.mojom b/headless/lib/browser/devtools_api/deprecated_domain_h.template
similarity index 58%
copy from cc/ipc/frame_sink_id.mojom
copy to headless/lib/browser/devtools_api/deprecated_domain_h.template
index b8fb286fe883dc8cc0782d867ed452861f85b268..e430a104e8d02b1284461a8a4457cc43215443f3 100644
--- a/cc/ipc/frame_sink_id.mojom
+++ b/headless/lib/browser/devtools_api/deprecated_domain_h.template
@@ -1,10 +1,7 @@
+// This file is generated
+
 // Copyright 2016 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 cc.mojom;
-
-struct FrameSinkId {
-  uint32 client_id;
-  uint32 sink_id;
-};
+#include "headless/public/devtools/domains/{{domain.domain | camelcase_to_hacker_style }}.h"