@NonNull
    Bundle toBundle() {
        Bundle bundle = new Bundle();
        if (toolbarColor != null) {
            bundle.putInt(EXTRA_TOOLBAR_COLOR, toolbarColor);
        }
        if (secondaryToolbarColor != null) {
            bundle.putInt(EXTRA_SECONDARY_TOOLBAR_COLOR, secondaryToolbarColor);
        }
        if (navigationBarColor != null) {
            bundle.putInt(EXTRA_NAVIGATION_BAR_COLOR, navigationBarColor);
        }
        return bundle;
    }
Packs the parameters into a {@link Bundle}.
For backward compatibility and ease of use, the names of keys and the structure of the Bundle
are the same as that of Intent extras prior to introducing the themes.
customtabs/src/android/support/customtabs/CustomTabColorSchemeParams.java