BotBuilder-Samples/CSharp/capability-BotInApps/WinPhone81/MainPage.xaml

<forms:WindowsPhonePage
    x:Class="WorkingWithWebview.WinPhone81.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:WorkingWithWebview.WinPhone81"
    xmlns:forms="using:Xamarin.Forms.Platform.WinRT"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">

    <Grid>

    </Grid>
</forms:WindowsPhonePage>