Revert of [Cronet] Remove JSON serialization of CronetEngine.Builder

components/cronet/android/java/src/org/chromium/net/CronetEngineBuilderList.template

Index: components/cronet/android/java/src/org/chromium/net/CronetEngineBuilderList.template
diff --git a/components/cronet/android/java/src/org/chromium/net/CronetEngineBuilderList.template b/components/cronet/android/java/src/org/chromium/net/CronetEngineBuilderList.template
new file mode 100644
index 0000000000000000000000000000000000000000..f30a09fa4978ddb92fffb87b41c26f8ea5be91b2
--- /dev/null
+++ b/components/cronet/android/java/src/org/chromium/net/CronetEngineBuilderList.template
@@ -0,0 +1,14 @@
+// Copyright 2014 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.
+
+package org.chromium.net;
+
+// A simple auto-generated interface used to list config params as used by
+// both org.chromium.net.CronetEngine.Builder and
+// components/cronet/url_request_context_config.h
+public interface CronetEngineBuilderList {
+#define DEFINE_CONTEXT_CONFIG(x) public static final String x = #x;
+#include "components/cronet/url_request_context_config_list.h"
+#undef DEFINE_CONTEXT_CONFIG
+}