RFR:8170868: DefaultProxySelector should use system defaults on Windows, MacOS and Gnome

[Zeller, Arno]

Hi Chris,

thanks for your comments! I adjusted the change to contain your suggestions and slightly modified 
src/java.base/share/classes/java/net/doc-files/net-properties.html  to refer to macOS .
Also found some missing adjustments of the copyright year myself...

>Some smaller comments and observations ( I'm still reviewing and testing ):
...
>2) unix/native/libnet/DefaultProxySelector.c
>
>    You have changes to make g_strv_length available, but then
>    count the proxies in the list manually. Maybe just use
>    g_strv_length.
Removed reference to g_strv_length - I simply forgot to delete it after changing my code to iterate over the list.

>    Nit: L 167 / 358    parameter indentation
Fixed.

>3) windows/native/libnet/DefaultProxySelector.c
>
>    The HINTERNET session could be set lazily, for the case
>    where there are no auto proxy settings. Not sure if it
>    worth it though.
I would like to keep the current approach because it avoids the need of locking to ensure that the initialization is 
done only by one thread.

>    The indentation of the main body of XXX_getSystemProxies
>    could be reduced a little if:
>      if (WinHttpGetIEProxyConfigForCurrentUser(&ie_proxy_config) == FALSE)
>        return NULL;
Done.

>4) macosx/native/libnet/DefaultProxySelector.c
>
>    The indentation of the main body of XXX_getSystemProxies
>    could be reduced a little if:
>     proxyDicRef = CFNetworkCopySystemProxySettings();
>     if (proxyDicRef == NULL)
>        return NULL;
Done.


>5) I personally prefer the code of the old createProxy. Was there
>    specific reason why you changed it?
Sorry for this - another leftover from a former change. I reverted back to the original. 

>6) Can you generally check the line lengths in all files, and try
>    where possible to keep it below 100, e.g. some comments could
>    easily be wrapped.
Done.

>7) I would like to add jtreg tags to test/java/net/ProxySelector/
>    SystemProxies.java to have it run in any automated test systems.
>    There would be no failure mode of this test, as it requires
>    manually inspecting the output, but it would at least give some
>    coverage to this new code. Something like:
>      /*
>       * @test
>       * @bug 8170868
>       * @summary Basic test to provide some coverage of system proxy code.
>Will
>       * always pass. Should be run manually for specific systems to inspect
>output.
>       * @run/othervm -Djava.net.useSystemProxies=true SystemProxies
>       */
Done.

The new webrev can be found at:
http://cr.openjdk.java.net/~clanger/webrevs/8170868.4/

Best regards,
Arno