Inflate taskbar all apps in abstract slide-in view.

All apps can now be dismissed via the scrim or swiping down. To properly
behave as an AFW, the apps view can no longer be within the taskbar's
layout, and will instead add and remove itself from the drag layer.

Test: Manual
Bug: 204696617
Change-Id: I86a0ffc06faa653c65b3797a57ba6512c6874221

src/com/android/launcher3/allapps/BaseAllAppsContainerView.java

@@ -249,6 +249,10 @@ public abstract class BaseAllAppsContainerView<T extends Context & ActivityConte
      * Returns whether the view itself will handle the touch event or not.
      */
     public boolean shouldContainerScroll(MotionEvent ev) {
+        // Scroll if not within the container view (e.g. over large-screen scrim).
+        if (!mActivityContext.getDragLayer().isEventOverView(this, ev)) {
+            return true;
+        }
         // TODO(b/216203409) Support dragging down from bottom sheet divider, if present.
         AllAppsRecyclerView rv = getActiveRecyclerView();
         if (rv == null) {