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

content/shell/renderer/layout_test/blink_test_runner.cc

 // Copyright (c) 2012 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.
 
 #include "content/shell/renderer/layout_test/blink_test_runner.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <clocale>
@@ skipping 686 matching lines @@
   plugins::PluginPlaceholder* placeholder =
       new plugins::PluginPlaceholder(render_view()->GetMainRenderFrame(), frame,
                                      params, "<div>Test content</div>");
   return placeholder->plugin();
 }
 
 float BlinkTestRunner::GetDeviceScaleFactorForTest() const {
   return render_view()->GetDeviceScaleFactorForTest();
 }
 
+void BlinkTestRunner::RunIdleTasks(const base::Closure& callback) {
+    SchedulerRunIdleTasks(callback);
+}
+
 bool BlinkTestRunner::AddMediaStreamVideoSourceAndTrack(
     blink::WebMediaStream* stream) {
   DCHECK(stream);
 #if defined(ENABLE_WEBRTC)
   return AddVideoTrackToMediaStream(
       base::WrapUnique(new MockVideoCapturerSource()),
       false,  // is_remote
       false,  // is_readonly
       stream);
 #else
@@ skipping 265 matching lines @@
   get_bluetooth_events_callbacks_.pop_front();
   callback.Run(events);
 }
 
 void BlinkTestRunner::ReportLeakDetectionResult(
     const LeakDetectionResult& report) {
   Send(new ShellViewHostMsg_LeakDetectionDone(routing_id(), report));
 }
 
 }  // namespace content