Add support for passing exception up from the child thread.

BUG=None
TEST=stress_unittest.py

Change-Id: I1e46e91bc2c26902d7d325d16b97393170122232
Reviewed-on: https://gerrit.chromium.org/gerrit/37087
Tested-by: Craig Harrison <craigdh@chromium.org>
Reviewed-by: Dennis Jeffrey <dennisjeffrey@chromium.org>
Reviewed-by: Prashanth Balasubramanian <beeps@chromium.org>
Commit-Ready: Craig Harrison <craigdh@chromium.org>
2 files changed