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
diff --git a/src/com/android/launcher3/Launcher.java b/src/com/android/launcher3/Launcher.java
index 253a7c7..fa63885 100644
--- a/src/com/android/launcher3/Launcher.java
+++ b/src/com/android/launcher3/Launcher.java
@@ -121,6 +121,7 @@
 import com.android.launcher3.dot.DotInfo;
 import com.android.launcher3.dragndrop.DragController;
 import com.android.launcher3.dragndrop.DragLayer;
+import com.android.launcher3.dragndrop.DragOptions;
 import com.android.launcher3.dragndrop.DragView;
 import com.android.launcher3.folder.FolderGridOrganizer;
 import com.android.launcher3.folder.FolderIcon;
@@ -2863,6 +2864,10 @@
         return false;
     }
 
+    public DragOptions getDefaultWorkspaceDragOptions() {
+        return new DragOptions();
+    }
+
     private static class NonConfigInstance {
         public Configuration config;
         public Bitmap snapshot;