Todd Volkert a4f2ad984d Fix context.dart to properly handle nested zones (#7189)
This fixes an infinite loop in the code that walks the parent
context chain looking for a variable.

This also includes a fix in build_info.dart whereby if the context
is set but the config is not yet set, we were trying to dereference
null.
2016-12-07 19:51:27 -08:00
..
2016-11-27 07:46:54 -08:00