Provide final callbacks before remove CustomContent (issue 11169651)

Change-Id: I0c30d58a4380f4525dcabf54a0cabf3789031ba6
diff --git a/src/com/android/launcher3/Workspace.java b/src/com/android/launcher3/Workspace.java
index 7a16474..bbe0946 100644
--- a/src/com/android/launcher3/Workspace.java
+++ b/src/com/android/launcher3/Workspace.java
@@ -557,6 +557,12 @@
         mWorkspaceScreens.remove(CUSTOM_CONTENT_SCREEN_ID);
         mScreenOrder.remove(CUSTOM_CONTENT_SCREEN_ID);
         removeView(customScreen);
+
+        if (mCustomContentCallbacks != null) {
+            mCustomContentCallbacks.onScrollProgressChanged(0);
+            mCustomContentCallbacks.onHide();
+        }
+
         mCustomContentCallbacks = null;
 
         // Ensure that the current page and default page are maintained.