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

content/public/test/layouttest_support.h

 // 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.
 
 #ifndef CONTENT_PUBLIC_TEST_LAYOUTTEST_SUPPORT_H_
 #define CONTENT_PUBLIC_TEST_LAYOUTTEST_SUPPORT_H_
 
 #include <stddef.h>
 
 #include <string>
@@ skipping 120 matching lines @@
 void EnableAutoResizeMode(RenderView* render_view,
                           const blink::WebSize& min_size,
                           const blink::WebSize& max_size);
 void DisableAutoResizeMode(RenderView* render_view,
                            const blink::WebSize& new_size);
 
 // Provides a text dump of the contents of the given page state.
 std::string DumpBackForwardList(std::vector<PageState>& page_state,
                                 size_t current_index);
 
+// Run all pending idle tasks immediately, and then invoke callback.
+void SchedulerRunIdleTasks(const base::Closure& callback);
+
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_TEST_LAYOUTTEST_SUPPORT_H_