Set up a place holder tile for desktop

Create a placeholder tile in recents for desktop.
It is based on launcher task information. With extra flag indicating it
is for desktop.
When it is clicked, it will call sysui to show apps on desktop.

Test: manually verify that desktop tasks do not show up separately in
recents
Bug: 244348395

Change-Id: I8535a54e1545841cd988d4770e6fc5e857277cda

quickstep/src/com/android/quickstep/views/TaskView.java

@@ -88,6 +88,7 @@ import com.android.launcher3.util.ViewPool.Reusable;
 import com.android.quickstep.RecentsModel;
 import com.android.quickstep.RemoteAnimationTargets;
 import com.android.quickstep.RemoteTargetGluer.RemoteTargetHandle;
+import com.android.quickstep.SystemUiProxy;
 import com.android.quickstep.TaskIconCache;
 import com.android.quickstep.TaskOverlayFactory;
 import com.android.quickstep.TaskThumbnailCache;
@@ -708,6 +709,11 @@ public class TaskView extends FrameLayout implements Reusable {
         RecentsView recentsView = getRecentsView();
         RemoteTargetHandle[] remoteTargetHandles = recentsView.mRemoteTargetHandles;
         RunnableList runnableList = new RunnableList();
+        if (mTask != null && mTask.desktopTile) {
+            // clicked on desktop
+            SystemUiProxy.INSTANCE.get(getContext()).showDesktopApps();
+            return runnableList;
+        }
         if (ENABLE_QUICKSTEP_LIVE_TILE.get() && isRunningTask() && remoteTargetHandles != null) {
             if (!mIsClickableAsLiveTile) {
                 return runnableList;