In Canary, crash if either UI or IO thread don't respond for 30 secs.

This is to catch hangs in issue like 288265.

R=jar@chromium.org

NOTRY=true

Review URL: https://codereview.chromium.org/24945002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225802 0039d316-1c4b-4281-b951-d872f2087c98
[chromedriver] Add a test for no hang if a tab crashes.

BUG=none
NOTRY=true

Review URL: https://codereview.chromium.org/24999010

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225803 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225803