Create UI tests for showing the snackbar and undoing it

PiperOrigin-RevId: 242908955
Change-Id: Idd51e34df11412a00432e27e50c2a52239ee972e
diff --git a/src/main/java/com/google/android/libraries/feed/common/concurrent/TaskQueue.java b/src/main/java/com/google/android/libraries/feed/common/concurrent/TaskQueue.java
index bf5370c..89d78ac 100644
--- a/src/main/java/com/google/android/libraries/feed/common/concurrent/TaskQueue.java
+++ b/src/main/java/com/google/android/libraries/feed/common/concurrent/TaskQueue.java
@@ -370,6 +370,10 @@
     }
   }
 
+  public boolean isIdle() {
+    return !hasBacklog() && currentTask == null;
+  }
+
   @VisibleForTesting
   boolean hasBacklog() {
     synchronized (lock) {