Remove the window from being a target for motion events when it is destroyed.

If window was destroyed when touch was pressed this destroyed
window was still considered as a target for motion events.
In some cases this could result with hang up inside event dispatch procedure.

Change-Id: I2ede17a40b14b2f509ab3d2560abb65292324f45

services/java/com/android/server/WindowManagerService.java

@@ -2149,6 +2149,7 @@ public class WindowManagerService extends IWindowManager.Stub
     private void removeWindowInnerLocked(Session session, WindowState win) {
         mKeyWaiter.finishedKey(session, win.mClient, true,
                 KeyWaiter.RETURN_NOTHING);
+        mKeyWaiter.releaseMotionTarget(win);
         mKeyWaiter.releasePendingPointerLocked(win.mSession);
         mKeyWaiter.releasePendingTrackballLocked(win.mSession);
 
@@ -6120,6 +6121,12 @@ public class WindowManagerService extends IWindowManager.Stub
             }
         }
 
+        void releaseMotionTarget(WindowState win) {
+            if (mMotionTarget == win) {
+                mMotionTarget = null;
+            }
+        }
+
         MotionEvent finishedKey(Session session, IWindow client, boolean force,
                 int returnWhat) {
             if (DEBUG_INPUT) Slog.v(