GitLab

1. Refactor out app_list_bubble_border so that it can be used for launcher
tooltip border.
2. UI polish: increase padding, make tooltip single line, reduce maximum
tooltip width.

BUG=133292
TEST=manual

Review URL: https://chromiumcodereview.appspot.com/10834140

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@149987 0039d316-1c4b-4281-b951-d872f2087c98