Apply HSTS to WebSocket

Fixes https://www.w3.org/Bugs/Public/show_bug.cgi?id=27554.

Author: annevk

source

@@ -2673,6 +2673,7 @@ a.setAttribute('href', 'http://example.com/'); // change the content attribute d
     <p>The following terms are defined in the WHATWG URL standard: <ref spec=URL></p>
 
     <ul class="brief">
+     <li><dfn data-noexport="" data-x="concept-domain" data-x-href="https://url.spec.whatwg.org/#concept-domain">domain</dfn>
      <li><dfn data-noexport="">URL</dfn>
      <li><dfn data-noexport="" data-x="concept-url-origin" data-x-href="https://url.spec.whatwg.org/#concept-url-origin">Origin</dfn> of URLs
      <li><dfn data-noexport="">Absolute URL</dfn>
@@ -92811,6 +92812,20 @@ interface <dfn>WebSocket</dfn> : <span>EventTarget</span> {
    settings object</span> has a scheme component that is itself a secure protocol, e.g. HTTPS, then
    throw a <code>SecurityError</code> exception and abort these steps.</p></li>
 
+   <li>
+    <p>If <var>secure</var> is false, <var>host</var> is a <span
+    data-x="concept-domain">domain</span>, and matching <var>host</var> per <a
+    href="https://tools.ietf.org/html/rfc6797#section-8.2">Known HSTS Host Domain Name Matching</a>
+    results in either a superdomain match with an asserted <code data-x="">includeSubDomains</code>
+    directive or a congruent match (with or without an asserted <code
+    data-x="">includeSubDomains</code> directive), then run these substeps: <ref spec=HSTS></p>
+
+    <ol>
+     <li><p>Set <var>secure</var> to true.</p></li>
+
+     <li><p>If <var>port</var> is 80, set <var>port</var> to 443.</p></li>
+    </ol>
+
    <li>
 
     <p>If <var>port</var> is a port to which the user agent is configured to block access, then
@@ -117846,6 +117861,9 @@ INSERT INTERFACES HERE
    <dd><cite><a href="https://dvcs.w3.org/hg/webperf/raw-file/tip/specs/HighResolutionTime/Overview.html">High Resolution Time</a></cite>, J. Mann. W3C.</dd>
    <!-- or http://www.w3.org/TR/hr-time/ ? it's highly unclear what URL is the one that would have the latest changes -->
 
+   <dt id="refsHSTS">[HSTS]</dt>
+   <dd><cite><a href="https://tools.ietf.org/html/rfc6797">HSTS</a></cite>, J. Hodges, C. Jackson, A. Barth. IETF.</dd>
+
    <dt id="refsHTML">[HTML]</dt>
    <dd><cite><a href="https://html.spec.whatwg.org/">HTML</a></cite>, I. Hickson. WHATWG.</dd>