[11u] RFR: 8217429: WebSocket over authenticating proxy fails to send Upgrade headers

[Baesken, Matthias]

Hi Götz , the backport looks good to me .

Best regards, Matthias

>Hi
>
>I downport this for 11.0.10-Oracle parity.  
>http://cr.openjdk.java.net/~goetz/wr20/8217429-websocket_headers-jdk11/01/
>
>I had to add include of HttpRequestImpl in Utils.java to make it compile. 
>http://cr.openjdk.java.net/~goetz/wr20/8217429-websocket_headers-jdk11/01/src/java.net.http/share/classes/jdk/internal/net/http/common/Utils.java.udiff.html
>
>Please review.
>
>Original change:
>https://bugs.openjdk.java.net/browse/JDK-8217429
>http://hg.openjdk.java.net/jdk/jdk/rev/41fa3e6f2785