Accessibility focus not cleared on temporary detach.

1. There was a path for removing a view without clearing its accessibility focus.
   Then when we try to draw the focused rectangle we get an exception since the
   accessibility focused view is not attached to the view tree when computing
   the location of the rectangel to draw.

bug:7297191

Change-Id: I81e3c35e830e27cf95e73accb665629d0c456afb

Author: sganov

core/java/android/view/ViewGroup.java

@@ -3912,6 +3912,7 @@ protected void attachViewToParent(View child, int index, LayoutParams params) {
      * @see #removeDetachedView(View, boolean)
      */
     protected void detachViewFromParent(View child) {
+        child.clearAccessibilityFocus();
         removeFromArray(indexOfChild(child));
     }
 
@@ -3933,6 +3934,7 @@ protected void detachViewFromParent(View child) {
      * @see #removeDetachedView(View, boolean)
      */
     protected void detachViewFromParent(int index) {
+        getChildAt(index).clearAccessibilityFocus();
         removeFromArray(index);
     }