Initiate Hotseat drag from long pressing corresponding Taskbar item

When you long press on the taskbar hotseat item, the following happens:
- We start a system drag and drop with an invisible drag shadow
- We create a new DragOptions with the simulatedDndStartPoint set to the
  drag down position, and tell Launcher to use that for the next drag
- We perform a long click on the equivalent Hotseat item in Launcher
- We pass the drag events of that operation to Launcher's DragController

This allows Launcher to handle the entire drag operation, including the
pre-drag (with popup), and taskbar already hides when the drag starts.

Test: Long press items in taskbar hotseat, able to drag them to workspace

Bug: 179886115
Bug: 171917176
Change-Id: I576b80cb1bd0225cdc91cf7689fdee0481265109

quickstep/src/com/android/launcher3/taskbar/TaskbarController.java

@@ -170,7 +170,14 @@ public class TaskbarController {
 
             @Override
             public View.OnLongClickListener getItemOnLongClickListener() {
-                return mDragController::startDragOnLongClick;
+                return view -> {
+                    if (mLauncher.hasBeenResumed() && view.getTag() instanceof ItemInfo) {
+                        alignRealHotseatWithTaskbar();
+                        return mDragController.startWorkspaceDragOnLongClick(view);
+                    } else {
+                        return mDragController.startSystemDragOnLongClick(view);
+                    }
+                };
             }
 
             @Override