@Override
        public boolean mayLaunchUrl(ICustomTabsCallback callback, Uri url,
                                    Bundle extras, List<Bundle> otherLikelyBundles) {
            return CustomTabsService.this.mayLaunchUrl(
                    new CustomTabsSessionToken(callback, getSessionIdFromBundle(extras)),
                    url, extras, otherLikelyBundles);
        }
File is a splash image to be shown on top of a Trusted Web Activity while the web contents
are loading.
customtabs/src/android/support/customtabs/CustomTabsService.java