Fix DevToolsManagerTest.TestObserver flakiness.

content/browser/devtools/devtools_manager.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_BROWSER_DEVTOOLS_DEVTOOLS_MANAGER_H_
 #define CONTENT_BROWSER_DEVTOOLS_DEVTOOLS_MANAGER_H_
 
 #include <map>
 #include <set>
 #include <string>
@@ skipping 36 matching lines @@
   virtual ~DevToolsManager();
 
   DevToolsManagerDelegate* delegate() const { return delegate_.get(); }
 
   void AddObserver(Observer* observer);
   void RemoveObserver(Observer* observer);
 
   void RenderViewCreated(WebContents* web_contents, RenderViewHost* rvh);
   void AgentHostChanged(scoped_refptr<DevToolsAgentHost> agent_host);
 
-  static void SetObserverThrottleIntervalForTest(base::TimeDelta interval);
+  typedef base::Callback<void(base::Closure)> Scheduler;
+  void SetSchedulerForTest(Scheduler scheduler);
 
  private:
   friend struct DefaultSingletonTraits<DevToolsManager>;
 
   void UpdateTargetList();
   void UpdateTargetListThrottled();
   void NotifyTargetListChanged(const Observer::TargetList& targets);
 
   scoped_ptr<DevToolsManagerDelegate> delegate_;
   ObserverList<Observer> observer_list_;
   std::set<DevToolsAgentHost*> attached_hosts_;
   bool update_target_list_required_;
   bool update_target_list_scheduled_;
   base::CancelableClosure update_target_list_callback_;
-
-  static base::TimeDelta observer_throttle_interval_;
+  Scheduler scheduler_;
 
   DISALLOW_COPY_AND_ASSIGN(DevToolsManager);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_DEVTOOLS_DEVTOOLS_MANAGER_H_