Cannot interact with dialogs when IME is up and on not touch explored popups.

1. If the last touch explored location is within the active window we
   used to click on exact location if it is within the accessibility
   focus otherwise in the accessibility focus center. If the last touch
   explored location is not within the active window we used to just
   click there. This breaks in the case were one has touch explored
   at a given place in the current window and now a dialog opens *not*
   covering the touch explored location. If one uses swipes to move
   accessibility focus i.e. to traverse the dialog without touching
   it one cannot activate anything because the touch explorer is using
   the last touch explored location that is outside of the active
   window e.g the dialog.

   The solution is to clear the last touch explored location when a
   window opens or accessibility focus moves. If the last touch
   explored location is null we are clicking in the accessibility
   focus location.

bug:6620911

2. There is a bug in the window manager that does not notify a
   window that its location has changed (bug:6623031). This breaks
   accessibility interaction with dialogs that have input because
   when the IME is up the dialog is moved but not notified. Now
   the accessibility layer gets incorrect location for the
   accessibility focus and the window bounds.

   The soluion is when the accessibility manager service calls
   into the remove thress to obtain some accessibility node infos
   it passes the window left and top which it gets from the
   window manager. These values are used to update the attach info
   window left and top so all accessibility node infos emitted
   from that window had correct bounds in screen coordinates.

bug:6620796

Change-Id: I18914f2095c55cfc826acf5277bd94b776bda0c8