Add tests for webRequest events and frame unload

chrome/test/data/extensions/api_test/webrequest/test_unload2.js

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+runTests([
+  // Load a slow page in a tab and close it.
+  function loadSlowTabAndClose() {
+    const url = getSlowURL('slow-single-main-frame');
+
+    expect([
+      { label: 'onBeforeRequest',
+        event: 'onBeforeRequest',
+        details: {
+          type: 'main_frame',
+          url,
+          frameUrl: url,
+        }
+      },
+      { label: 'onBeforeSendHeaders',
+        event: 'onBeforeSendHeaders',
+        details: {
+          type: 'main_frame',
+          url,
+        },
+      },
+      { label: 'onSendHeaders',
+        event: 'onSendHeaders',
+        details: {
+          type: 'main_frame',
+          url,
+        },
+      },
+      { label: 'onErrorOccurred',
+        event: 'onErrorOccurred',
+        details: {
+          type: 'main_frame',
+          url,
+          fromCache: false,
+          error: 'net::ERR_ABORTED',
+        },
+      }],
+      [['onBeforeRequest', 'onBeforeSendHeaders', 'onSendHeaders',
+        'onErrorOccurred']]);
+
+    var callbackDone = chrome.test.callbackAdded();
+
+    waitUntilSendHeaders('main_frame', url, function() {
+      // Cancels load and triggers onErrorOccurred.
+      chrome.tabs.remove(tabId, callbackDone);
+    }),
+    chrome.tabs.update(tabId, {url});
+  },
+]);