Only close the chromium tree for catastrophic failure steps.
Only close the chromium tree for catastrophic failure steps.

bot_update, update, runhooks and compile.

BUG=387399

Review URL: https://codereview.chromium.org/480233008

git-svn-id: 239fca9b83025a0b6f823aeeca02ba5be3d9fd76@291692 0039d316-1c4b-4281-b951-d872f2087c98

eunchong/build,eunchong/build,eunchong/build,eunchong/build