Update {virtual,override} to follow C++11 style in content.

content/browser/power_profiler/power_data_provider_ia_win.h

Index: content/browser/power_profiler/power_data_provider_ia_win.h
diff --git a/content/browser/power_profiler/power_data_provider_ia_win.h b/content/browser/power_profiler/power_data_provider_ia_win.h
index 427a5fa202a7f7ce57bc5cd14ffdc457b2504383..68d220ded91d568a667487e6554e8a496eab6d12 100644
--- a/content/browser/power_profiler/power_data_provider_ia_win.h
+++ b/content/browser/power_profiler/power_data_provider_ia_win.h
@@ -15,12 +15,14 @@ class PowerDataProviderIA : public PowerDataProvider {
  public:
   PowerDataProviderIA();
 
-  virtual ~PowerDataProviderIA();
+  ~PowerDataProviderIA() override;
 
   bool Initialize();
-  virtual PowerEventVector GetData() override;
-  virtual base::TimeDelta GetSamplingRate() override;
-  virtual AccuracyLevel GetAccuracyLevel() override { return High; }
+
+  // PowerDataProvider:
+  PowerEventVector GetData() override;
+  base::TimeDelta GetSamplingRate() override;
+  AccuracyLevel GetAccuracyLevel() override { return High; }
 
  private:
   CIntelPowerGadgetLib energy_lib_;