Screen Magnifier: Change keyboard shortcut from [CTRL + brightness] to [CTRL + ALT + brightness]

BUG=153961

Review URL: https://chromiumcodereview.appspot.com/11035051

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@160776 0039d316-1c4b-4281-b951-d872f2087c98
1 file changed