Bug 1608545 - ensure userContextId inherited from relatedTab is used throughout addTab and test for it, r=dao

Differential Revision: https://phabricator.services.mozilla.com/D60017

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

browser/base/content/tabbrowser.js

@@ -2634,12 +2634,17 @@
         this.tabContainer.getAttribute("overflow") != "true" &&
         this.animationsEnabled;
 
+      // Related tab inherits current tab's user context unless a different
+      // usercontextid is specified
+      if (userContextId == null && openerTab) {
+        userContextId = openerTab.getAttribute("usercontextid") || 0;
+      }
+
       this.setTabAttributes(t, {
         animate,
         noInitialLabel,
         aURI,
         userContextId,
-        openerTab,
         skipBackgroundNotify,
         pinned,
         skipAnimation,
@@ -3111,7 +3116,6 @@
         noInitialLabel,
         aURI,
         userContextId,
-        openerTab,
         skipBackgroundNotify,
         pinned,
         skipAnimation,
@@ -3126,12 +3130,6 @@
         }
       }
 
-      // Related tab inherits current tab's user context unless a different
-      // usercontextid is specified
-      if (userContextId == null && openerTab) {
-        userContextId = openerTab.getAttribute("usercontextid") || 0;
-      }
-
       if (userContextId) {
         tab.setAttribute("usercontextid", userContextId);
         ContextualIdentityService.setTabStyle(tab);

browser/components/contextualidentity/test/browser/browser_relatedTab.js

@@ -23,6 +23,11 @@ add_task(async function() {
     1,
     "Related tab (relatedToCurrent) inherits current tab's usercontextid"
   );
+  is(
+    relatedTab.linkedBrowser.contentPrincipal.userContextId,
+    1,
+    "Related tab's browser actually inherits the current tab's usercontextid"
+  );
   BrowserTestUtils.removeTab(relatedTab);
 
   gBrowser.selectedTab = tab;
@@ -35,6 +40,11 @@ add_task(async function() {
     2,
     "Related tab (relatedToCurrent) with overridden usercontextid"
   );
+  is(
+    relatedTab.linkedBrowser.contentPrincipal.userContextId,
+    2,
+    "Related tab's browser actually gets overridden usercontextid"
+  );
   BrowserTestUtils.removeTab(relatedTab);
 
   gBrowser.selectedTab = tab;
@@ -51,6 +61,11 @@ add_task(async function() {
     1,
     "Related tab (referrer) inherits current tab's usercontextid"
   );
+  is(
+    relatedTab.linkedBrowser.contentPrincipal.userContextId,
+    1,
+    "Related tab's browser (referrer) actually inherits the current tab's usercontextid"
+  );
   BrowserTestUtils.removeTab(relatedTab);
 
   gBrowser.selectedTab = tab;
@@ -68,6 +83,11 @@ add_task(async function() {
     2,
     "Related tab (referrer) with overridden usercontextid"
   );
+  is(
+    relatedTab.linkedBrowser.contentPrincipal.userContextId,
+    2,
+    "Related tab's browser (referrer) actually gets overridden usercontextid"
+  );
   BrowserTestUtils.removeTab(relatedTab);
 
   BrowserTestUtils.removeTab(tab);