Change the default of HttpAuthDynamicParams::enable_negotiate_port to false.

The expected default is false, as that is what is used at other layers:
  * net::HttpAuthPreferences
  * prefs::kEnableAuthNegotiatePort
  * key::kEnableAuthNegotiatePort

Using true can cause problems with integrated auth, as it constructs SPNs in the less common way.

Bug: 924746
Change-Id: I2d09f0c72aa2ac8d8f60c1e2adfeb92c379d336b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2225531
Commit-Queue: Eric Roman <eroman@chromium.org>
Commit-Queue: Will Harris <wfh@chromium.org>
Reviewed-by: Matt Menke <mmenke@chromium.org>
Reviewed-by: Will Harris <wfh@chromium.org>
Auto-Submit: Eric Roman <eroman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#774396}

services/network/public/mojom/network_service.mojom

@@ -149,7 +149,7 @@ struct HttpAuthDynamicParams {
 
   // True if Negotiate SPNs (service principal names) should include ports
   // when the port isn't a standard port (80 or 443).
-  bool enable_negotiate_port = true;
+  bool enable_negotiate_port = false;
 
   // Whether NTLM V2 is enabled on POSIX platforms. No effect elsewhere.
   bool ntlm_v2_enabled = true;