[Predictive Back] Dismiss taskbar all apps's scroll bar during swipe gesture [2/n]

Bug: 327490078
Flag: aconfig com.android.launcher3.enable_predictive_back_gesture TEAMFOOD
Test: manual
Change-Id: I0c6585e6374db9412c8399ce3fdaf57348043d36
diff --git a/quickstep/src/com/android/launcher3/taskbar/allapps/TaskbarAllAppsSlideInView.java b/quickstep/src/com/android/launcher3/taskbar/allapps/TaskbarAllAppsSlideInView.java
index 70d25b9..82a2f45 100644
--- a/quickstep/src/com/android/launcher3/taskbar/allapps/TaskbarAllAppsSlideInView.java
+++ b/quickstep/src/com/android/launcher3/taskbar/allapps/TaskbarAllAppsSlideInView.java
@@ -35,6 +35,7 @@
 import com.android.launcher3.DeviceProfile;
 import com.android.launcher3.Insettable;
 import com.android.launcher3.R;
+import com.android.launcher3.allapps.AllAppsRecyclerView;
 import com.android.launcher3.anim.AnimatorListeners;
 import com.android.launcher3.anim.PendingAnimation;
 import com.android.launcher3.config.FeatureFlags;
@@ -211,6 +212,11 @@
         super.onScaleProgressChanged();
         mAppsView.setClipChildren(!mIsBackProgressing);
         mAppsView.getAppsRecyclerViewContainer().setClipChildren(!mIsBackProgressing);
+        AllAppsRecyclerView rv = mAppsView.getActiveRecyclerView();
+        if (rv != null && rv.getScrollbar() != null) {
+            rv.getScrollbar().setVisibility(
+                    mIsBackProgressing ? INVISIBLE : VISIBLE);
+        }
     }
 
     @Override