@Override
        public boolean receiveFile(ICustomTabsCallback callback, @NonNull Uri uri,
                @FilePurpose int purpose, @Nullable Bundle extras) {
            return CustomTabsService.this.receiveFile(
                    new CustomTabsSessionToken(callback, getSessionIdFromBundle(extras)),
                    uri, purpose, extras);
        }
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