Add testRunner.runIdleTasks() to force idle tasks to run.

components/test_runner/test_runner.h

 // Copyright 2014 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.
 
 #ifndef COMPONENTS_TEST_RUNNER_TEST_RUNNER_H_
 #define COMPONENTS_TEST_RUNNER_TEST_RUNNER_H_
 
 #include <stdint.h>
 
 #include <deque>
@@ skipping 570 matching lines @@
   // Causes the beforeinstallprompt event to be sent to the renderer.
   void DispatchBeforeInstallPromptEvent(
       int request_id,
       const std::vector<std::string>& event_platforms,
       v8::Local<v8::Function> callback);
 
   // Resolve the beforeinstallprompt event with the matching request id.
   void ResolveBeforeInstallPromptPromise(int request_id,
                                          const std::string& platform);
 
+  // Immediately run all pending idle tasks, including all pending
+  // requestIdleCallback calls.  Invoke the callback when all
+  // idle tasks are complete.
+  void RunIdleTasks(v8::Local<v8::Function> callback);
+
   // Calls setlocale(LC_ALL, ...) for a specified locale.
   // Resets between tests.
   void SetPOSIXLocale(const std::string& locale);
 
   // MIDI function to control permission handling.
   void SetMIDIAccessorResult(bool result);
 
   // Simulates a click on a Web Notification.
   void SimulateWebNotificationClick(const std::string& title, int action_index);
 
@@ skipping 216 matching lines @@
   blink::WebImage drag_image_;
 
   base::WeakPtrFactory<TestRunner> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TestRunner);
 };
 
 }  // namespace test_runner
 
 #endif  // COMPONENTS_TEST_RUNNER_TEST_RUNNER_H_