Handle SystemGestureRegion in TaskbarDragLayer

- Currently user can tap on taskbar icons when in persitent mode when a popup is visible on screen.
we are making it so that touch event is not performed at view level and get dismissed before at drag layer.

Test: Presubmit, Manual
Bug: 320229858
Flag: NONE
Change-Id: I9a76faa0e282317d808ba0f55b49741dc7b750a3

quickstep/src/com/android/launcher3/taskbar/TaskbarDragLayer.java

@@ -146,6 +146,15 @@ public class TaskbarDragLayer extends BaseDragLayer<TaskbarActivityContext> {
         onDestroy(true);
     }
 
+    @Override
+    protected boolean isEventWithinSystemGestureRegion(MotionEvent ev) {
+        final float x = ev.getX();
+        final float y = ev.getY();
+
+        return x >= mSystemGestureRegion.left && x < getWidth() - mSystemGestureRegion.right
+                && y >= mSystemGestureRegion.top;
+    }
+
     @Override
     protected boolean canFindActiveController() {
         // Unlike super class, we want to be able to find controllers when touches occur in the