Update from https://crrev.com/309415

Review URL: https://codereview.chromium.org/822713002
diff --git a/base/base.gypi b/base/base.gypi
index 5ec4142..349308c 100644
--- a/base/base.gypi
+++ b/base/base.gypi
@@ -263,6 +263,7 @@
           'json/json_reader.h',
           'json/json_string_value_serializer.cc',
           'json/json_string_value_serializer.h',
+          'json/json_value_converter.cc',
           'json/json_value_converter.h',
           'json/json_writer.cc',
           'json/json_writer.h',