Fix browser crash when closing popups (issue 3631).
Fix browser crash when closing popups (issue 3631).

The Google Bookmarks bookmarklet opens a popup window that allows you to bookmark a page. When the window closes we crash because we dereference a NULL TabContents pointer the we get from GetSelectedTabContents(). This fixes that.

Review URL: http://codereview.chromium.org/8185

git-svn-id: dd90618784b6a4b323ea0c23a071cb1c9e6f2ac7@4093 4ff67af0-8c30-449e-8e8b-ad334ec8d88c

wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser,wistoch/meego-app-browser