Add FirstScreenWidget plugin interface

package com.android.systemui.plugins;

import android.view.ViewGroup;

import com.android.systemui.plugins.annotations.ProvidesInterface;

/**

 * Implement this interface to wrap the widget on the first home screen, e.g. to add new content.

 */

@ProvidesInterface(action = FirstScreenWidget.ACTION, version = FirstScreenWidget.VERSION)

public interface FirstScreenWidget extends Plugin {

    String ACTION = "com.android.systemui.action.PLUGIN_FIRST_SCREEN_WIDGET";

    int VERSION = 1;

    void onWidgetUpdated(ViewGroup widgetView);

}