Make OAuth2TokenService and subclasses take delegate by unique_ptr

chrome/browser/chromeos/settings/device_oauth2_token_service.h

Index: chrome/browser/chromeos/settings/device_oauth2_token_service.h
diff --git a/chrome/browser/chromeos/settings/device_oauth2_token_service.h b/chrome/browser/chromeos/settings/device_oauth2_token_service.h
index d3182eaf0b40cf73ffd6deb352573533880235e2..b23e93a2ec0474786faf70009d3f20b679cb3afa 100644
--- a/chrome/browser/chromeos/settings/device_oauth2_token_service.h
+++ b/chrome/browser/chromeos/settings/device_oauth2_token_service.h
@@ -67,8 +67,8 @@ class DeviceOAuth2TokenService
   void OnValidationCompleted(GoogleServiceAuthError::State error) override;
 
   // Use DeviceOAuth2TokenServiceFactory to get an instance of this class.
-  // Ownership of |token_encryptor| will be taken.
-  explicit DeviceOAuth2TokenService(DeviceOAuth2TokenServiceDelegate* delegate);
+  explicit DeviceOAuth2TokenService(
+      std::unique_ptr<DeviceOAuth2TokenServiceDelegate> delegate);
   ~DeviceOAuth2TokenService() override;
 
   // Flushes |pending_requests_|, indicating the specified result.
@@ -78,12 +78,13 @@ class DeviceOAuth2TokenService
   // Signals failure on the specified request, passing |error| as the reason.
   void FailRequest(RequestImpl* request, GoogleServiceAuthError::State error);
 
+  DeviceOAuth2TokenServiceDelegate* GetDeviceDelegate();
+  const DeviceOAuth2TokenServiceDelegate* GetDeviceDelegate() const;
+
   // Currently open requests that are waiting while loading the system salt or
   // validating the token.
   std::vector<PendingRequest*> pending_requests_;
 
-  DeviceOAuth2TokenServiceDelegate* delegate_;
-
   DISALLOW_COPY_AND_ASSIGN(DeviceOAuth2TokenService);
 };