Add new, hidden MotionEvent flag for partially obscured windows.

Bug: 26677796
Change-Id: Ic4219b883bb760495e6172ef61e84e9725876ef6

Author: Michael Wright

core/java/android/view/MotionEvent.java

@@ -416,6 +416,21 @@ public final class MotionEvent extends InputEvent implements Parcelable {
      */
     public static final int FLAG_WINDOW_IS_OBSCURED = 0x1;
 
+    /**
+     * This flag indicates that the window that received this motion event is partly
+     * or wholly obscured by another visible window above it.  This flag is set to true
+     * even if the event did not directly pass through the obscured area.
+     * A security sensitive application can check this flag to identify situations in which
+     * a malicious application may have covered up part of its content for the purpose
+     * of misleading the user or hijacking touches.  An appropriate response might be
+     * to drop the suspect touches or to take additional precautions to confirm the user's
+     * actual intent.
+     *
+     * Unlike FLAG_WINDOW_IS_OBSCURED, this is actually true.
+     * @hide
+     */
+    public static final int FLAG_WINDOW_IS_PARTIALLY_OBSCURED = 0x2;
+
     /**
      * Private flag that indicates when the system has detected that this motion event
      * may be inconsistent with respect to the sequence of previously delivered motion events,