Widen the initial size of the settings app.

This prevents the vertical scrollbar on the Languages overlay being
obscured for common cases.

BUG=296816
TEST=Open Settings via the App Launcher, and open 'Language and Input
Settings' under advanced settings. The overlay should fit horizontally
and there should be no horizontal scrollbar. There may still be a
vertical scrollbar. Not that Settings App remembers its size if it was
opened before, so you may need to do this in an empty profile.

Review URL: https://codereview.chromium.org/24519003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@225653 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 225653