Creating the skeleton ChatView 

This XAML file will contain the view that lists the messages we have sent and the messages we have received. It's quite a large file to create, so for this part, I suggest that you copy the XAML and study every step carefully:

1. Create a new XAML ContentPage in the Views folder called ChatView.
2. Add XML namespaces for Chat.Selectors and Chat.Converters and call them selectors and converters.
3. Add a ContentPage.Resources node. This will contain the resources for this view.
4. Add ScrollView as the page content. ScrollView should only be able to scroll on iOS to handle when the onscreen keyboard is visible. On Android, this isn't necessary and causes some other problems. Use OnPlatform to set Orientation to Neither for Android and Vertical for iOS. 
5. Add Grid as the only child of ScrollView and name it MainGrid by setting the x:Name property to MainGrid.

6. Create a RowDefinitions element that contains three rows...