Add a control group to the SiteIsolationExtensionsActive. It corresponds to the Disabled group of t…

chrome/browser/site_details_browsertest.cc

Index: chrome/browser/site_details_browsertest.cc
diff --git a/chrome/browser/site_details_browsertest.cc b/chrome/browser/site_details_browsertest.cc
index eb30679f60d23f5b183a6c8af8185d95a3563ca1..d24f0f16f608ba9030a995a31b0816ee027a8568 100644
--- a/chrome/browser/site_details_browsertest.cc
+++ b/chrome/browser/site_details_browsertest.cc
@@ -1097,7 +1097,10 @@ IN_PROC_BROWSER_TEST_F(SiteDetailsBrowserTest, VerifyFieldTrialGroup) {
       group = "FieldTrial";
     }
   } else {
-    group = "Default";
+    if (base::FieldTrialList::FindFullName("SiteIsolationExtensions").empty())
+      group = "Default";
+    else
+      group = "Control";
   }
 
   EXPECT_TRUE(IsInTrialGroup("SiteIsolationExtensionsActive", group));