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

components/scheduler/test/renderer_scheduler_test_support.h

Index: components/scheduler/test/renderer_scheduler_test_support.h
diff --git a/components/scheduler/test/renderer_scheduler_test_support.h b/components/scheduler/test/renderer_scheduler_test_support.h
new file mode 100644
index 0000000000000000000000000000000000000000..aee29f1c90006f796e8fb66cf4ad898a7e763105
--- /dev/null
+++ b/components/scheduler/test/renderer_scheduler_test_support.h
@@ -0,0 +1,14 @@
+// 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.
+
+#include "base/bind.h"
+
+namespace scheduler {
+
+class RendererScheduler;
+
+extern void RunIdleTasksForTesting(RendererScheduler* scheduler,
+                                   const base::Closure& callback);
+
+}