[chromedriver] Wait 60 seconds for chrome to start up on all OS and 30 seconds for chrome shutdown on Mac and Linux.

Drive by fix:
1. Fix API document for method Chrome::GetWebViewIds in chrome.h
2. Remove one of the duplicate 'cleanup' steps in run_buildbot_steps.py

BUG=chromedriver:672

Review URL: https://codereview.chromium.org/136143003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245759 0039d316-1c4b-4281-b951-d872f2087c98