Disable extensions when inspecting DOM UI

This disables front-end extensions when DevTools are attached to
privileged pages.

Bug: 1059577, 795595
Change-Id: I0971fd993bee63eea347ffa800c3cc72e09ba334
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2128732
Commit-Queue: Andrey Kosyakov <[email protected]>
Reviewed-by: Benedikt Meurer <[email protected]>
Reviewed-by: Tim van der Lippe <[email protected]>
diff --git a/front_end/Tests.js b/front_end/Tests.js
index 99de8eb..303f1e5 100644
--- a/front_end/Tests.js
+++ b/front_end/Tests.js
@@ -1165,6 +1165,23 @@
     this.takeControl();
   };
 
+  TestSuite.prototype.waitForTestResultsAsMessage = function() {
+    const onMessage = event => {
+      if (!event.data.testOutput) {
+        return;
+      }
+      top.removeEventListener('message', onMessage);
+      const text = event.data.testOutput;
+      if (text === 'PASS') {
+        this.releaseControl();
+      } else {
+        this.fail(text);
+      }
+    };
+    top.addEventListener('message', onMessage);
+    this.takeControl();
+  };
+
   TestSuite.prototype._overrideMethod = function(receiver, methodName, override) {
     const original = receiver[methodName];
     if (typeof original !== 'function') {