Remove taskbar when display mirroring starts

Bug: 397095099
Change-Id: I0d21650af45aec084c0b48b50e22e8072d3f9192
Test: adb shell settings put secure mirror_built_in_display 1
Flag: com.android.server.display.feature.flags.enable_display_content_mode_management
diff --git a/quickstep/src/com/android/launcher3/taskbar/TaskbarManager.java b/quickstep/src/com/android/launcher3/taskbar/TaskbarManager.java
index 46802c3..6cd2979 100644
--- a/quickstep/src/com/android/launcher3/taskbar/TaskbarManager.java
+++ b/quickstep/src/com/android/launcher3/taskbar/TaskbarManager.java
@@ -747,7 +747,11 @@
     /**
      * Signal from SysUI indicating that system decorations should be removed from the display.
      */
-    public void onDisplayRemoveSystemDecorations(int displayId) {}
+    public void onDisplayRemoveSystemDecorations(int displayId) {
+        // The display mirroring starts. The handling logic is the same as when removing a
+        // display.
+        onDisplayRemoved(displayId);
+    }
 
     private void removeActivityCallbacksAndListeners() {
         if (mActivity != null) {