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/BaseQuickstepLauncher.java

@@ -35,6 +35,7 @@ import android.view.View;
 import androidx.annotation.Nullable;
 
 import com.android.launcher3.config.FeatureFlags;
+import com.android.launcher3.dragndrop.DragOptions;
 import com.android.launcher3.model.WellbeingModel;
 import com.android.launcher3.popup.SystemShortcut;
 import com.android.launcher3.proxy.ProxyActivityStarter;
@@ -83,6 +84,8 @@ public abstract class BaseQuickstepLauncher extends Launcher
 
     private @Nullable TaskbarController mTaskbarController;
     private final TaskbarStateHandler mTaskbarStateHandler = new TaskbarStateHandler(this);
+    // Will be updated when dragging from taskbar.
+    private DragOptions mWorkspaceDragOptions = new DragOptions();
 
     @Override
     protected void onCreate(Bundle savedInstanceState) {
@@ -269,6 +272,15 @@ public abstract class BaseQuickstepLauncher extends Launcher
         return mTaskbarController != null && mTaskbarController.isViewInTaskbar(v);
     }
 
+    @Override
+    public DragOptions getDefaultWorkspaceDragOptions() {
+        return mWorkspaceDragOptions;
+    }
+
+    public void setWorkspaceDragOptions(DragOptions dragOptions) {
+        mWorkspaceDragOptions = dragOptions;
+    }
+
     @Override
     public void useFadeOutAnimationForLauncherStart(CancellationSignal signal) {
         QuickstepAppTransitionManagerImpl appTransitionManager =