YouTube V3 on Windows Phone 8.1 Silverlight throws exception on Back Button

1. Create Windows Phone 8.1 Silverlight project, add single page
2. Perform YouTube login using version 1.8.1.1140 of Google.Apis.Youtube.v3 
nuGet library.
3. After login, hit back button on main page. Unhandled exception thrown. Must 
handle to keep app from crashing, then hit back button again in order to 
actually exit the app

What is the expected output? What do you see instead?
Expected behavior is no exceptions thrown. Youtube login control shouldn't care 
about back button after it's been dismissed. Instead it appears to be active 
invisibly, handling the back button, and thrown an exception.

What version of the product are you using? 1.8.1.1140
What is your operating system? Dev OS = Windows 8.1, running OS = Windows Phone 
8.1
What is your IDE? Visual Studio 2013
What is the .NET framework version? 4.5

Please provide any additional information below.

Original issue reported on code.google.com by bc3t...@gmail.com on 23 Aug 2014 at 5:49

Merged into: #475

kelvinRosa / google-api-dotnet-client

YouTube V3 on Windows Phone 8.1 Silverlight throws exception on Back Button #484