Android how to call from activity to child view

I have an activity that contains a webview, in the event screen rotation or not I want to call a function in side the webview. How can I do it:

    public void onConfigurationChanged(Configuration newConfig) {
            super.onConfigurationChanged(newConfig);
            int orientation=newConfig.orientation;
            switch(orientation) {
                case Configuration.ORIENTATION_LANDSCAPE:
                    ORIENTATION = Configuration.ORIENTATION_LANDSCAPE;
/// Call function inside webview
                    break;
                case Configuration.ORIENTATION_PORTRAIT:
                    ORIENTATION = Configuration.ORIENTATION_PORTRAIT;
/// Call function inside webview
                    break;

            }
        }

Thanks you so much