Wrap a try block around getting a screenshot.

If webdriver goes down we won't be able to get a screenshot.  Throwing
an exception in the thread pool will lock the test.

BUG=None
TEST=Manual, ran it

Change-Id: Ic5232bd7053f42de5c4d9a8c5335d75c383ef44d
Reviewed-on: https://chromium-review.googlesource.com/168077
Tested-by: Kris Rambish <krisr@chromium.org>
Reviewed-by: Bindu Mahadev <bmahadev@chromium.org>
1 file changed