Fix more leaks in the blink unit tests.

WebFrameClients need to call WebFrame::close() in frameDetached();
otherwise the reference will leak.

BUG=none

Review URL: https://codereview.chromium.org/181013004

git-svn-id: svn://svn.chromium.org/blink/trunk@167963 bbb929c8-8fbe-4397-9dbb-9b2b20218538