Re-land 261836 "Restore --child-clean-exit behavior for ASan/LSan..."

This change uncovered a crash in unrelated code on ChromeOS, and was reverted in
r262012. The crash has been filed under http://crbug.com/360622. As a temporary
measure I'm re-landing the change under "#if !defined(OS_CHROMEOS)".

BUG=360622, 324216, 307043
TBR=jam@chromium.org
TEST=compile
NOTRY=true

Review URL: https://codereview.chromium.org/227563004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@262184 0039d316-1c4b-4281-b951-d872f2087c98
3 files changed