<rdar://problem/7231652> 
REGRESSION (r48446): While a <select> popup menu is open, the
rest of the WebView doesn't respond to mouse move events.

Reviewed by Sam Weinig.

* platform/win/PopupMenuWin.cpp:
(WebCore::translatePoint):
New helper function that translates a point between HWND coordinates.
        
(WebCore::PopupMenu::show):
Protect the PopupMenu if someone removes the <select> in response to a mouse
event. Handle WM_HOST_WINDOW_MOUSEMOVE events.
        
(WebCore::PopupMenu::wndProc):
in the WM_MOUSEMOVE handler, if the mouse is not over the popup, post a 
WM_HOST_WINDOW_MOUSEMOVE event so that the host window (the WebView) gets the
mouse move event.



git-svn-id: http://svn.webkit.org/repository/webkit/trunk@48529 268f45cc-cd09-0410-ab3c-d52691b4dbfc