Notify client side of window movement.

Add a one way method to notify Views that the window has moved
on the screen. Fixes issues arising from the IME popping up and
translating the window that uses it. Accessibility was left unaware
of these movements and was drawing the box around the wrong widgets.
Similarly PopupWindow used getLocationOnScreen to determine how
much screen real estate was above and below the anchor point to
determine where to put an anchored window.

Fixes bug 6623031.

Change-Id: I4731a94d5424c1ec77bf1729fba8fc9ea34cae46