Make OutputDeveloperMessageCode an enum class

chrome/browser/banners/app_banner_debug_log.h

 // Copyright 2015 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_BANNERS_APP_BANNER_DEBUG_LOG_H_
 #define CHROME_BROWSER_BANNERS_APP_BANNER_DEBUG_LOG_H_
 
 #include <string>
 
 namespace content {
 class WebContents;
 }  // namespace content
 
 namespace banners {
 
 // Error message strings used to notify developers via the console.
 
-enum OutputDeveloperMessageCode {
+enum class OutputDeveloperMessageCode {
   kRendererRequestCancel,
   kManifestEmpty,
   kNoManifest,
   kNoIconMatchingRequirements,
   kCannotDownloadIcon,
   kNoMatchingServiceWorker,
   kNoIconAvailable,
   kUserNavigatedBeforeBannerShown,
   kStartURLNotValid,
   kManifestDisplayStandaloneFullscreen,
@@ skipping 15 matching lines @@
 // Logs a message to the main console if a banner could not be shown
 // and the engagement checks have been bypassed.
 void OutputDeveloperNotShownMessage(content::WebContents* web_contents,
                                     OutputDeveloperMessageCode code,
                                     const std::string& param,
                                     bool is_debug_mode);
 
 }  // namespace banners
 
 #endif  // CHROME_BROWSER_BANNERS_APP_BANNER_DEBUG_LOG_H_