code: private void adaptBreadCrumbBackgroundColor() {
          if (breadCrumbToolbar != null) {
              GradientDrawable background = (GradientDrawable) ContextCompat
                      .getDrawable(this, R.drawable.breadcrumb_background);
              background.setColor(breadCrumbBackgroundColor);
              ViewUtil.setBackground(getBreadCrumbToolbar(), background);
          }
      }
docs: Adapts the background color of the toolbar, which is used to show the bread crumb of the
  currently selected navigation preferences, when using the split screen layout.