Makes SupportsFeature virtual and adds a virtual destructor to Browser.
Makes SupportsFeature virtual and adds a virtual destructor to Browser.

BUG=none
TEST=none

Review URL: http://codereview.chromium.org/69022

git-svn-id: http://src.chromium.org/svn/trunk/src@13931 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

Former-commit-id: e36fa9be7756418f8f3a6ef8dffd9cd6ab2d4ca9
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