GitLab

If the BookmarkBarNode isn't loaded (yet) then we shouldn't be creating any bookmark buttons.  This fixes the crashes reported in ExtensionInstallUIBrowserTest.

BUG=44548
TEST=browser_tests, unit_tests, trybots

Review URL: http://codereview.chromium.org/6209001

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@72197 0039d316-1c4b-4281-b951-d872f2087c98