Add WebSocket mixed content wpt

Also modify common.sub.js so it doesn't try to make insecure connections
in secure contents.

Firefox passes the new mixed-content test in all contexts.

Safari fails the new mixed-content test in all contexts.

Change-Id: Ia3e82096e738095a04d3c7b5f8d21819f5de2faf
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4624022
Reviewed-by: Kenichi Ishibashi <bashi@chromium.org>
Commit-Queue: Adam Rice <ricea@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1161711}

third_party/blink/web_tests/external/wpt/websockets/constants.sub.js

@@ -1,14 +1,14 @@
 const __SERVER__NAME = "{{host}}";
 const __PATH = "echo";
 
-var __SCHEME;
-var __PORT;
-if (url_has_variant('wss')) {
-  __SCHEME = 'wss';
-  __PORT = "{{ports[wss][0]}}";
-} else if (url_has_flag('h2')) {
+let __SCHEME;
+let __PORT;
+if (url_has_flag('h2')) {
   __SCHEME = 'wss';
   __PORT = "{{ports[h2][0]}}";
+} else if (url_has_variant('wss') || location.protocol === 'https:') {
+  __SCHEME = 'wss';
+  __PORT = "{{ports[wss][0]}}";
 } else {
   __SCHEME = 'ws';
   __PORT = "{{ports[ws][0]}}";
@@ -74,6 +74,12 @@ function CreateWebSocketWithRepeatedProtocolsCaseInsensitive() {
   wsocket = new WebSocket(url, ["echo", "eCho"]);
 }
 
+function CreateInsecureWebSocket() {
+  IsWebSocket();
+  const url = `ws://${__SERVER__NAME}:{{ports[ws][0]}}/${__PATH}`;
+  return new WebSocket(url);
+}
+
 function CreateWebSocket(isProtocol, isProtocols) {
   IsWebSocket();
   const url = SCHEME_DOMAIN_PORT + "/" + __PATH;

third_party/blink/web_tests/external/wpt/websockets/mixed-content.https.any.js

@@ -0,0 +1,7 @@
+// META: global=window,worker
+// META: script=constants.sub.js
+
+test(() => {
+  assert_throws_dom('SecurityError', () => CreateInsecureWebSocket(),
+                    'constructor should throw');
+}, 'constructing an insecure WebSocket in a secure context should throw');

third_party/blink/web_tests/external/wpt/websockets/mixed-content.https.any.sharedworker-expected.txt

@@ -0,0 +1,4 @@
+This is a testharness.js-based test.
+FAIL constructing an insecure WebSocket in a secure context should throw assert_throws_dom: constructor should throw function "() => CreateInsecureWebSocket()" did not throw
+Harness: the test ran to completion.
+