DevTools: [timeline tree view] (unattributed) costs include extension overhead in Domain grouping

Source/devtools/front_end/timeline/TimelineTreeView.js

Index: Source/devtools/front_end/timeline/TimelineTreeView.js
diff --git a/Source/devtools/front_end/timeline/TimelineTreeView.js b/Source/devtools/front_end/timeline/TimelineTreeView.js
index 0bf6de842e1dd08fe1c0206a41248d53cff99abc..62719ff88942934f31239d1134cc04748c59a033 100644
--- a/Source/devtools/front_end/timeline/TimelineTreeView.js
+++ b/Source/devtools/front_end/timeline/TimelineTreeView.js
@@ -188,11 +188,14 @@ WebInspector.TimelineTreeView.prototype = {
          */
         function groupByDomain(groupSubdomains, node)
         {
-            var parsedURL = (WebInspector.TimelineTreeView.eventURL(node.event) || "").asParsedURL();
+            var url = WebInspector.TimelineTreeView.eventURL(node.event) || "";
+            if (url.startsWith("extensions::"))
+                return groupSubdomains ? WebInspector.UIString("Chrome Extensions Overhead") : url;
+            var parsedURL = url.asParsedURL();
             if (!parsedURL)
                 return "";
             if (parsedURL.scheme === "chrome-extension") {
-                var url = parsedURL.scheme + "://" + parsedURL.host;
+                url = parsedURL.scheme + "://" + parsedURL.host;
                 var displayName = executionContextNamesByOrigin.get(url);
                 return displayName ? WebInspector.UIString("Chrome Extension: %s", displayName) : url;
             }