Remove const qualifier from function return type

chrome/browser/extensions/api/copresence/copresence_api.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 CHROME_BROWSER_EXTENSIONS_API_COPRESENCE_COPRESENCE_API_H_
 #define CHROME_BROWSER_EXTENSIONS_API_COPRESENCE_COPRESENCE_API_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 38 matching lines @@
 
   // These accessors will always return an object (except during shutdown).
   // If the object doesn't exist, they will create one first.
   copresence::CopresenceManager* manager();
 
   // A registry containing the app id's associated with every subscription.
   SubscriptionToAppMap& apps_by_subscription_id() {
     return apps_by_subscription_id_;
   }
 
-  const std::string auth_token(const std::string& app_id) const;
+  std::string auth_token(const std::string& app_id) const;
 
   void set_api_key(const std::string& app_id,
                    const std::string& api_key);
 
   void set_auth_token(const std::string& app_id,
                       const std::string& token);
 
   // Delete all current copresence data, including stored device IDs.
   void ResetState();
 
   // Manager override for testing.
   void set_manager_for_testing(
       scoped_ptr<copresence::CopresenceManager> manager);
 
   // Registers the preference for saving our device IDs.
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
 
   // BrowserContextKeyedAPI implementation.
   static BrowserContextKeyedAPIFactory<CopresenceService>* GetFactoryInstance();
 
  private:
   friend class BrowserContextKeyedAPIFactory<CopresenceService>;
 
   // CopresenceDelegate implementation
   void HandleMessages(const std::string& app_id,
                       const std::string& subscription_id,
                       const std::vector<copresence::Message>& message) override;
   void HandleStatusUpdate(copresence::CopresenceStatus status) override;
   net::URLRequestContextGetter* GetRequestContext() const override;
-  const std::string GetPlatformVersionString() const override;
-  const std::string GetAPIKey(const std::string& app_id) const override;
+  std::string GetPlatformVersionString() const override;
+  std::string GetAPIKey(const std::string& app_id) const override;
   audio_modem::WhispernetClient* GetWhispernetClient() override;
   gcm::GCMDriver* GetGCMDriver() override;
-  const std::string GetDeviceId(bool authenticated) override;
+  std::string GetDeviceId(bool authenticated) override;
   void SaveDeviceId(bool authenticated, const std::string& device_id) override;
 
   // BrowserContextKeyedAPI implementation.
   static const char* service_name() { return "CopresenceService"; }
 
   PrefService* GetPrefService();
 
   bool is_shutting_down_;
   content::BrowserContext* const browser_context_;
 
@@ skipping 40 matching lines @@
                              COPRESENCE_SETAUTHTOKEN);
 
  protected:
   ~CopresenceSetAuthTokenFunction() override {}
   ExtensionFunction::ResponseAction Run() override;
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_COPRESENCE_COPRESENCE_API_H_