Loading a new tab does not dismiss Lookup

<rdar://problem/9138391> 

Rubber-stamped by Anders Carlsson.

* UIProcess/API/mac/WKView.mm:
(-[WKView viewDidMoveToWindow]):
Hide the dictionary popup when moving the WKView out of a window.



git-svn-id: svn://svn.chromium.org/blink/trunk@81721 bbb929c8-8fbe-4397-9dbb-9b2b20218538