Add the "virtual" keyword on method overrides that are missing it.

chrome/browser/policy/device_management_policy_provider.h

 // Copyright (c) 2010 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_POLICY_DEVICE_MANAGEMENT_POLICY_PROVIDER_H_
 #define CHROME_BROWSER_POLICY_DEVICE_MANAGEMENT_POLICY_PROVIDER_H_
 #pragma once
 
 #include <string>
 
@@ skipping 30 matching lines @@
 
   // ConfigurationPolicyProvider implementation:
   virtual bool Provide(ConfigurationPolicyStoreInterface* store);
 
   // DevicePolicyResponseDelegate implementation:
   virtual void HandlePolicyResponse(
       const em::DevicePolicyResponse& response);
   virtual void OnError(DeviceManagementBackend::ErrorCode code);
 
   // DeviceTokenFetcher::Observer implementation:
-  void OnTokenSuccess();
-  void OnTokenError();
-  void OnNotManaged();
+  virtual void OnTokenSuccess();
+  virtual void OnTokenError();
+  virtual void OnNotManaged();
 
   // True if a policy request has been sent to the device management backend
   // server and no response or error has yet been received.
   bool IsPolicyRequestPending() const { return policy_request_pending_; }
 
   bool waiting_for_initial_policies() const {
     return waiting_for_initial_policies_;
   }
 
   // Tells the provider that the passed in token service reference is about to
@@ skipping 80 matching lines @@
   int64 policy_refresh_error_delay_ms_;
   int64 token_fetch_error_delay_ms_;
   int64 unmanaged_device_refresh_rate_ms_;
 
   DISALLOW_COPY_AND_ASSIGN(DeviceManagementPolicyProvider);
 };
 
 }  // namespace policy
 
 #endif  // CHROME_BROWSER_POLICY_DEVICE_MANAGEMENT_POLICY_PROVIDER_H_