Bug 1532722 - Include cookies in ChannelMediaResource requests when CORS mode is use-credentials. r=bryce

Credit for fixing this goes to Alexey <a.s.datsyuk.s@gmail.com>.

Differential Revision: https://phabricator.services.mozilla.com/D59625

--HG--
extra : moz-landing-system : lando

dom/media/ChannelMediaResource.cpp

@@ -742,6 +742,10 @@ nsresult ChannelMediaResource::RecreateChannel() {
           ? nsILoadInfo::SEC_REQUIRE_CORS_DATA_INHERITS
           : nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_DATA_INHERITS;
 
+  if (element->GetCORSMode() == CORS_USE_CREDENTIALS) {
+    securityFlags |= nsILoadInfo::SEC_COOKIES_INCLUDE;
+  }
+
   MOZ_ASSERT(element->IsAnyOfHTMLElements(nsGkAtoms::audio, nsGkAtoms::video));
   nsContentPolicyType contentPolicyType =
       element->IsHTMLElement(nsGkAtoms::audio)