[DevTools] [PowerProfiler] Fix for browser crash with active timeline recording for capturing power.

content/browser/power_profiler/power_profiler_service.h

 // Copyright 2014 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_POWER_PROFILER_POWER_PROFILER_SERVICE_H_
 #define CONTENT_BROWSER_POWER_PROFILER_POWER_PROFILER_SERVICE_H_
 
 #include "base/basictypes.h"
 #include "base/memory/singleton.h"
 #include "base/observer_list.h"
 #include "base/task_runner.h"
 #include "base/timer/timer.h"
 #include "content/browser/power_profiler/power_data_provider.h"
 #include "content/browser/power_profiler/power_profiler_observer.h"
 #include "content/common/content_export.h"
 
 namespace content {
 
 // A class used to query power information and notify the observers.
 class CONTENT_EXPORT PowerProfilerService {
  public:
   static PowerProfilerService* GetInstance();
 
   // Add and remove an observer.
   void AddObserver(PowerProfilerObserver* observer);
   void RemoveObserver(PowerProfilerObserver* observer);
+  bool HasObserver(PowerProfilerObserver* observer) const {
+    return observers_.HasObserver(observer);
+  }
 
   bool IsAvailable();
 
   virtual ~PowerProfilerService();
 
  private:
   enum Status {
     UNINITIALIZED,
     INITIALIZED,  // Initialized, profiling has not started.
     PROFILING
@@ skipping 31 matching lines @@
   ObserverList<PowerProfilerObserver> observers_;
 
   scoped_ptr<PowerDataProvider> data_provider_;
 
   DISALLOW_COPY_AND_ASSIGN(PowerProfilerService);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_POWER_PROFILER_POWER_PROFILER_SERVICE_H_