GitLab

Don't create the virtual keyboard until it is first shown.  This helps
prevent some start-up races.

Also clean-up some of the object ownership between KeyboardController
and KeyboardLayoutManager.  Each pointer exists in only one or the
other object now.

BUG=none

Review URL: https://codereview.chromium.org/13932030

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@194580 0039d316-1c4b-4281-b951-d872f2087c98