public TrustedWebActivityIntentBuilder setSplashScreenParams(Bundle splashScreenParams) {
        mSplashScreenParams = splashScreenParams;
        return this;
    }
Sets the parameters of a splash screen shown while the web page is loading, such as
background color. See {@link TrustedWebUtils.SplashScreenParamKey} for a list of supported
parameters.

To provide the image for the splash screen, use {@link TrustedWebUtils#transferSplashImage},
prior to launching the intent.

It is recommended to also show the same splash screen in the app as soon as possible,
prior to establishing a CustomTabConnection. The Trusted Web Activity provider should
ensure seamless transition of the splash screen from the app onto the top of webpage
being loaded.

The splash screen will be removed on the first paint of the page, or when the page load
fails.
customtabs/src/android/support/customtabs/trusted/TrustedWebActivityIntentBuilder.java