Fix NPE of touch handling in StatusBarTouchController#onControllerInterceptTouchEvent

Postsubmit passes: https://android-build.corp.google.com/builds/abtd/run/L20300030001590062

Test: presubmit
Flag: NONE
Fix: 282945183
Change-Id: Idcf87f8cd45350c4876ea8b1ae2dffa5127bf27f
diff --git a/quickstep/src/com/android/launcher3/uioverrides/touchcontrollers/StatusBarTouchController.java b/quickstep/src/com/android/launcher3/uioverrides/touchcontrollers/StatusBarTouchController.java
index cda7855..d98e608 100644
--- a/quickstep/src/com/android/launcher3/uioverrides/touchcontrollers/StatusBarTouchController.java
+++ b/quickstep/src/com/android/launcher3/uioverrides/touchcontrollers/StatusBarTouchController.java
@@ -104,7 +104,7 @@
         if (!mCanIntercept) {
             return false;
         }
-        if (action == ACTION_MOVE) {
+        if (action == ACTION_MOVE && mDownEvents.contains(pid)) {
             float dy = ev.getY(idx) - mDownEvents.get(pid).y;
             float dx = ev.getX(idx) - mDownEvents.get(pid).x;
             if (mIsTrackpadReverseScroll) {