Update {virtual,override,final} to follow C++11 style in components, round 2.

components/policy/core/common/proxy_policy_provider.h

Index: components/policy/core/common/proxy_policy_provider.h
diff --git a/components/policy/core/common/proxy_policy_provider.h b/components/policy/core/common/proxy_policy_provider.h
index de1ba3351bfb6454d9753a1627573698638b8b93..9066b562d6c43cdcdb7cd51cb6d2411ce7bab945 100644
--- a/components/policy/core/common/proxy_policy_provider.h
+++ b/components/policy/core/common/proxy_policy_provider.h
@@ -41,17 +41,17 @@ class POLICY_EXPORT ProxyPolicyProvider
       public ConfigurationPolicyProvider::Observer {
  public:
   ProxyPolicyProvider();
-  virtual ~ProxyPolicyProvider();
+  ~ProxyPolicyProvider() override;
 
   // Updates the provider this proxy delegates to.
   void SetDelegate(ConfigurationPolicyProvider* delegate);
 
   // ConfigurationPolicyProvider:
-  virtual void Shutdown() override;
-  virtual void RefreshPolicies() override;
+  void Shutdown() override;
+  void RefreshPolicies() override;
 
   // ConfigurationPolicyProvider::Observer:
-  virtual void OnUpdatePolicy(ConfigurationPolicyProvider* provider) override;
+  void OnUpdatePolicy(ConfigurationPolicyProvider* provider) override;
 
  private:
   ConfigurationPolicyProvider* delegate_;