Augment long-press tests for typing on the virtual keyboard.

BUG=301640

Review URL: https://codereview.chromium.org/25233003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@226113 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 226113