Add a 'hidden' option to chrome.app.window.create()

This also adds AppWindow.show()/hide(), to manipulate the visibility of the
window once it has been created.

[email protected],[email protected]
BUG=131742


Review URL: https://chromiumcodereview.appspot.com/11147037

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@164016 0039d316-1c4b-4281-b951-d872f2087c98
23 files changed