ThemeableBrowserOptions not working

Ionic Native
1

Screenshot_12

share and close button not visible

Screenshot_13

2 
const options: ThemeableBrowserOptions = {
     statusbar: {
         color: '#ffffffff'
     },
     toolbar: {
         height: 44,
         color: '#f0f0f0ff'
     },
     title: {
         color: '#003264ff',
         showPageTitle: true
     },
     backButton: {
         image: 'back',
         imagePressed: 'back_pressed',
         align: 'left',
         event: 'backPressed'
     },
     forwardButton: {
         image: 'forward',
         imagePressed: 'forward_pressed',
         align: 'left',
         event: 'forwardPressed'
     },
     closeButton: {
         image: 'close',
         imagePressed: 'close_pressed',
         align: 'left',
         event: 'closePressed'
     },
     customButtons: [
         {
             image: 'share',
             imagePressed: 'share_pressed',
             align: 'right',
             event: 'sharePressed'
         }
     ],
     menu: {
         image: 'menu',
         imagePressed: 'menu_pressed',
         title: 'Test',
         cancel: 'Cancel',
         align: 'right',
         items: [
             {
                 event: 'helloPressed',
                 label: 'Hello World!'
             },
             {
                 event: 'testPressed',
                 label: 'Test!'
             }
         ]
     },
     backButtonCanClose: true
};

const browser: ThemeableBrowserObject = this.themeableBrowser.create('https://ionic.io', '_blank', options);

i try this , but not working