WebAuthenticationBrokerUserControl.OnBrowserNavigationFailed throws ArgumentNullException when no network connectivity

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What steps will reproduce the problem?
1. Turn off network connectivity
2. Call AuthorizationCodeWPInstalledApp.AuthorizeAsync(string.Empty, 
CancellationToken.None)
3. ArgumentNullException is thrown at 
WebAuthenticationBrokerUserControl.xaml.cs#OnBrowserNavigationFailed

Line 69:
tcsAuthorizationCodeResponse.SetException(e.Exception);

What is the expected output? What do you see instead?
Should not set exception if the exception is null. Also, I can't seem to find a 
way to catch that exception from the app when using this API.

What version of the product are you using? Google.Apis.Auth.1.6.0.1-beta
What is your operating system? Windows 8
What is your IDE? Visual Studio 2013
What is the .NET framework version? .Net framework for WinPhone 8

Please provide any additional information below.

Original issue reported on code.google.com by kneri...@gmail.com on 18 Dec 2013 at 12:13

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Original comment by pele...@google.com on 29 Dec 2013 at 1:14

• Changed state: Accepted
• Added labels: Component-Auth, Milestone-Release1.8

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https://codereview.appspot.com/46440043/

Original comment by pele...@google.com on 9 Jan 2014 at 9:47

• Changed state: Started

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Original comment by pele...@google.com on 10 Jan 2014 at 5:01

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Original comment by pele...@google.com on 14 Jan 2014 at 11:35

• Changed state: Fixed