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

components/cronet/cronet_static.gypi

 # 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.
 
 {
   # This target is included into both 'cronet_static' and 'cronet_static_small'.
   'dependencies': [
     '../base/base.gyp:base',
     '../base/third_party/dynamic_annotations/dynamic_annotations.gyp:dynamic_annotations',
     'cronet_jni_headers',
+    'cronet_engine_builder_list',
     'cronet_url_request_java',
     'cronet_version',
     'cronet_version_header',
     'metrics',
   ],
   'sources': [
     'android/chromium_url_request.cc',
     'android/chromium_url_request.h',
     'android/chromium_url_request_context.cc',
     'android/chromium_url_request_context.h',
@@ skipping 49 matching lines @@
           'DATA_REDUCTION_PROXY_SUPPORT'
         ],
         'sources': [
           'android/cronet_data_reduction_proxy.cc',
           'android/cronet_data_reduction_proxy.h',
         ],
       }
     ],
   ],
 }