Provide AllApps item OnLongClickListener through ActivityContext.

This cleans up how alternative AllApps implementations such as Taskbar
and SecondaryDisplay override the default INSTANCE_ALL_APPS listener.
This change will also be helpful for Toast in Taskbar drag-n-drop.

Test: Manual
Bug: 289261756
Flag: n/a
Change-Id: I55eb881bcd1e210852d435a3ea2a6686ce0a9838

quickstep/src/com/android/launcher3/taskbar/allapps/TaskbarAllAppsViewController.java

@@ -20,7 +20,6 @@ import static com.android.launcher3.util.OnboardingPrefs.ALL_APPS_VISITED_COUNT;
 
 import com.android.launcher3.AbstractFloatingView;
 import com.android.launcher3.appprediction.AppsDividerView;
-import com.android.launcher3.appprediction.PredictionRowView;
 import com.android.launcher3.taskbar.NavbarButtonsViewController;
 import com.android.launcher3.taskbar.TaskbarControllers;
 import com.android.launcher3.taskbar.TaskbarStashController;
@@ -54,7 +53,6 @@ final class TaskbarAllAppsViewController {
         mOverlayController = taskbarControllers.taskbarOverlayController;
 
         mSlideInView.init(new TaskbarAllAppsCallbacks());
-        setUpIconLongClick();
         setUpAppDivider();
         setUpTaskbarStashing();
     }
@@ -69,15 +67,6 @@ final class TaskbarAllAppsViewController {
         mSlideInView.close(animate);
     }
 
-    private void setUpIconLongClick() {
-        mAppsView.setOnIconLongClickListener(
-                mContext.getDragController()::startDragOnLongClick);
-        mAppsView.getFloatingHeaderView()
-                .findFixedRowByType(PredictionRowView.class)
-                .setOnIconLongClickListener(
-                        mContext.getDragController()::startDragOnLongClick);
-    }
-
     private void setUpAppDivider() {
         mAppsView.getFloatingHeaderView()
                 .findFixedRowByType(AppsDividerView.class)