Disable dragging on fullscreen tasks.

This CL prevents dragging fullscreen tasks via caption.

Bug: 243683959
Test: Attempt to drag a fullscreen task, ensure dragging non-maximized
captions is unaffected.

Change-Id: I297f2e8b6d69aba29061ae008d9d51df03ae134c

libs/WindowManager/Shell/src/com/android/wm/shell/windowdecor/CaptionWindowDecorViewModel.java

@@ -199,6 +199,10 @@ public class CaptionWindowDecorViewModel implements WindowDecorViewModel<Caption
         }
 
         private void handleEventForMove(MotionEvent e) {
+            if (mTaskOrganizer.getRunningTaskInfo(mTaskId).getWindowingMode()
+                    == WINDOWING_MODE_FULLSCREEN) {
+                return;
+            }
             switch (e.getActionMasked()) {
                 case MotionEvent.ACTION_DOWN:
                     mDragPointerId  = e.getPointerId(0);