linux: extra shadow in prefs dialog
linux: extra shadow in prefs dialog

When we use gtk_scrolled_window_add_with_viewport, it sets its own
shadow.

BUG=16913

Review URL: http://codereview.chromium.org/159535

git-svn-id: http://src.chromium.org/svn/trunk/src@21884 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: ace536edcd274651f0fbd2dee4576b0a88df1727
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