@Nullable
    protected Matrix getSplashImageTransformationMatrix() {
        return null;
    }
Override to set a transformation matrix for the image displayed on a splash screen.
See {@link ImageView#setImageMatrix}.
Has any effect only if {@link #getSplashImageScaleType()} returns {@link
ImageView.ScaleType#MATRIX}.
customtabs/src/android/support/customtabs/trusted/LauncherActivity.java