code: protected final void addSharedElement(@NonNull String fromName, @NonNull String toName) {
          sharedElementNames.put(fromName, toName);
      }
docs: Used to register an element that will take part in the shared element transition. Maps the name used in the
  "from" view to the name used in the "to" view if they are not the same.
  
  @param fromName The transition name used in the "from" view
  @param toName The transition name used in the "to" view