I am building a .NET web application that authenticates Salesforce users using OAuth 2.0. Following the guide here, I was able to implement the web-server flow. However, now that I am getting farther along I decided to make a "launcher" Visualforce page that is available to the traditional Salesforce UI in addition to Salesforce1. This page has a button that the user clicks to open a new window to my application. My application then sends the user through https://login.salesforce.com/service/oauth2/authorize. After authentication, they are redirected back to my application with an OAuth token.
The problem with Salesforce1 for Android is that a Chrome browser window is opened when the user clicks the launch button in the Visualforce page. My application redirects them to the authorization url listed above, only now since they are no longer in the Salesforce1 app, they are asked to re-login to Salesforce through their browser. This seems less than optimal since they are already logged in through the native Android app. Is there a way to handle this type of authentication such that the user is not forced to re-authenticate from their web-browser?