Adding application name message in kiosk mode after user timeout

This is a security feature for a user who interacts with a kiosk device - making sure that he/she knows which application is running.

When a user interacts with the device after 2 minutes of inactivity, a message shows which application is running and who was the author.

When spoken feedback is turned on, the device will also narrowate the content of the message.

The message itself will slide in from the top and - after a short timeout - will automatically slide out again.

BUG=268453
TEST=unit test & visual test

Committed: https://src.chromium.org/viewvc/chrome?view=rev&revision=249921

Review URL: https://codereview.chromium.org/131353007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@250000 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 250000