Windows Phone Back Button doesnt work during AUTH flow

[GoogleCodeExporter]

Windows Phone application using Google Auth API fails Microsoft certification 
due to "back button" certification requirements.

1. Start oAuth flow by calling GoogleWebAuthorizationBroker.AuthorizeAsync
2. The actual app "page content" is replaced by a Google Login page 
3. Press back button on windows phone
4. Nothing happens, the google login page stays on screen. 

Expected output is that the google login page is removed and the "actual page 
content" is displayed. 

Google.Apis.Auth v1.6.0.16898 acquired from Nuget
Windows Phone 8 OS 
Visual Studio 2013
.Net for WindowsPhone8.0

Additional Info:
There is probably a related issue that happens intermittently. If I go through 
the authorization process i.e. login, authorize the app to access my info, 
accept, the view reverts back to the login page. Normally (correct behavior) 
the webbrowser control disappears and I am redirected to my app. But sometimes, 
that never happens, the login page keeps coming up no mater how many times I 
perform successful login and authorize the app to access my data, press 
"accept" button.

Original issue reported on code.google.com by im...@danglingconcepts.com on 2 Dec 2013 at 6:25

[GoogleCodeExporter]

Original comment by pele...@google.com on 3 Dec 2013 at 1:16

• Added labels: Component-Auth

[GoogleCodeExporter]

Original comment by pele...@google.com on 3 Dec 2013 at 1:17

• Changed state: Accepted

[GoogleCodeExporter]

For now, I did a quick and dirty fix in my application code after checking out 
the code of the component. The component is saving out the page.Content and 
setting a user control as Content of the page with the browser control. This of 
course does not handle the back button.
So what I have now is in my original Page I save out the page.Content. When 
Back button is pressed I check if the page.Content != mySavedOutContent and 
then set the savedOutContent to page.Content.
This will get me through the Microsoft certification process and hopefully not 
cause any side effects. 
Maybe if a function is added to cancel the "Auth" task and revert the original 
content back, it will be better to "call" from my app code to dispose 
everything cleanly.

Original comment by im...@danglingconcepts.com on 3 Dec 2013 at 9:13

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Original comment by pele...@google.com on 29 Dec 2013 at 1:15

• Added labels: Milestone-Release1.8

[GoogleCodeExporter]

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

Original comment by pele...@google.com on 30 Dec 2013 at 11:09

• Changed state: Started

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Original comment by pele...@google.com on 10 Jan 2014 at 5:00

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

• Changed state: Fixed