Remove TabContents from TabStripModelObserver::TabDetachedAt.

BUG=107201
TEST=no visible change


Review URL: https://chromiumcodereview.appspot.com/11293205

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@167122 0039d316-1c4b-4281-b951-d872f2087c98
gfx::Image Browser::GetCurrentPageIcon() const {
  WebContents* web_contents = chrome::GetActiveWebContents(this);
  FaviconTabHelper* favicon_tab_helper =
      web_contents ? FaviconTabHelper::FromWebContents(web_contents) : NULL;
  return favicon_tab_helper ? favicon_tab_helper->GetFavicon() : gfx::Image();
}

gfx::Image Browser::GetCurrentPageIcon() const {
  WebContents* web_contents = chrome::GetActiveWebContents(this);
  FaviconTabHelper* favicon_tab_helper =
      web_contents ? FaviconTabHelper::FromWebContents(web_contents) : NULL;
  return favicon_tab_helper ? favicon_tab_helper->GetFavicon() : gfx::Image();
}
