[TaskManager] Allow a Task to mutate its PID after creation

chrome/browser/task_manager/providers/task_provider.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_MANAGER_PROVIDERS_TASK_PROVIDER_H_
 #define CHROME_BROWSER_TASK_MANAGER_PROVIDERS_TASK_PROVIDER_H_
 
 #include "base/macros.h"
 #include "chrome/browser/task_manager/providers/task_provider_observer.h"
 
@@ skipping 32 matching lines @@
   // the observer if there's no one set.
   void ClearObserver();
 
  protected:
   // Used by concrete task providers to notify the observer of tasks addition/
   // removal/renderer unresponsive. These methods should only be called after
   // StartUpdating() has been called and before StopUpdating() is called.
   void NotifyObserverTaskAdded(Task* task) const;
   void NotifyObserverTaskRemoved(Task* task) const;
   void NotifyObserverTaskUnresponsive(Task* task) const;
+  void UpdateTaskProcessInfoAndNotifyObserver(
+      Task* existing_task,
+      base::ProcessHandle new_process_handle,
+      base::ProcessId new_process_id) const;
 
  private:
   // This will be called once an observer is set for this provider. When it is
   // called, the concrete provider must notify the observer of all pre-existing
   // tasks as well as track new addition and terminations and notify the
   // observer of these changes.
   virtual void StartUpdating() = 0;
 
   // This will be called once the observer is cleared, at which point the
   // provider can stop tracking tasks addition / removal and can clear its own
   // resources.
   virtual void StopUpdating() = 0;
 
   // We support only one single obsever which will be the sampler in this case.
   TaskProviderObserver* observer_;
 
   DISALLOW_COPY_AND_ASSIGN(TaskProvider);
 };
 
 }  // namespace task_manager
 
 #endif  // CHROME_BROWSER_TASK_MANAGER_PROVIDERS_TASK_PROVIDER_H_