Migrate ProcessesEventRouter to the new task manager

chrome/browser/task_management/providers/task_provider_observer.h

 // Copyright 2015 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 CHROME_BROWSER_TASK_MANAGEMENT_PROVIDERS_TASK_PROVIDER_OBSERVER_H_
 #define CHROME_BROWSER_TASK_MANAGEMENT_PROVIDERS_TASK_PROVIDER_OBSERVER_H_
 
 #include "base/macros.h"
 #include "chrome/browser/task_management/providers/task.h"
 
 namespace task_management {
 
 // Defines an interface for observing tasks addition / removal.
 class TaskProviderObserver {
  public:
   TaskProviderObserver() {}
   virtual ~TaskProviderObserver() {}
 
   // This notifies of the event that a new |task| has been created.
   virtual void TaskAdded(Task* task) = 0;
 
   // This notifies of the event that a |task| is about to be removed. The task
   // is still valid during this call, after that it may never be used again by
   // the observer and references to it must not be kept.
   virtual void TaskRemoved(Task* task) = 0;
 
+  // This notifies of the event that |task| has become unresponsive. This event
+  // is only for tasks representing renderer processes.
+  virtual void TaskUnresponsive(Task* task) {}
+
  private:
   DISALLOW_COPY_AND_ASSIGN(TaskProviderObserver);
 };
 
 }  // namespace task_management
 
 #endif  // CHROME_BROWSER_TASK_MANAGEMENT_PROVIDERS_TASK_PROVIDER_OBSERVER_H_