add a pref save when changing the visible icon count
add a pref save when changing the visible icon count

BUG=47201
TEST=Resize the browser action area and then force a shutdown.  Ensure that the change is persisted for the next launch.

Review URL: http://codereview.chromium.org/3791003

git-svn-id: http://src.chromium.org/svn/trunk/src@62545 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: 3d72ac40a912ab1d7be3e53d32858d8b5a61f723
meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser,meego-tablet-ux/meego-app-browser