Translate: adopt html lang attribute if valid value is provided

chrome/renderer/translate/translate_helper_metrics.h

 // Copyright 2013 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_RENDERER_TRANSLATE_TRANSLATE_HELPER_METRICS_H_
 #define CHROME_RENDERER_TRANSLATE_TRANSLATE_HELPER_METRICS_H_
 
 #include <string>
 
 #include "base/time.h"
 
 namespace TranslateHelperMetrics {
 
 // An indexing type to query each UMA entry name via GetMetricsName() function.
 // Note: |kMetricsEntries| should be updated when a new entry is added here.
 enum MetricsNameIndex {
   UMA_LANGUAGE_DETECTION,
   UMA_CONTENT_LANGUAGE,
+  UMA_HTML_LANG,
   UMA_LANGUAGE_VERIFICATION,
   UMA_TIME_TO_BE_READY,
   UMA_TIME_TO_LOAD,
   UMA_TIME_TO_TRANSLATE,
   UMA_USER_ACTION_DURATION,
   UMA_MAX,
 };
 
 // A page may provide a Content-Language HTTP header or a META tag.
 // TranslateHelper checks if a server provides a valid Content-Language.
-enum ContentLanguageType {
-  CONTENT_LANGUAGE_NOT_PROVIDED,
-  CONTENT_LANGUAGE_VALID,
-  CONTENT_LANGUAGE_INVALID,
-  CONTENT_LANGUAGE_MAX,
+enum LanguageCheckType {
+  LANGUAGE_NOT_PROVIDED,
+  LANGUAGE_VALID,
+  LANGUAGE_INVALID,
+  LANGUAGE_MAX,
 };
 
 // When a valid Content-Language is provided, TranslateHelper checks if a
 // server provided Content-Language matches to a language CLD determined.
 enum LanguageVerificationType {
   LANGUAGE_VERIFICATION_CLD_DISABLED,
   LANGUAGE_VERIFICATION_CLD_ONLY,
   LANGUAGE_VERIFICATION_UNKNOWN,
   LANGUAGE_VERIFICATION_CLD_AGREE,
   LANGUAGE_VERIFICATION_CLD_DISAGREE,
   LANGUAGE_VERIFICATION_MAX,
 };
 
 // Called after TranslateHelper verifies a server providing Content-Language
-// header. |provided_code| contains a Content-Language header value which
+// header. |provided_code| contains a Content-Language header value which a
 // server provides. It can be empty string when a server doesn't provide it.
 // |revised_code| is a value modified by format error corrector.
 void ReportContentLanguage(const std::string& provided_code,
                            const std::string& revised_code);
 
+// Called after TranslateHelper verifies a page providing html lang attribute.
+// |provided_code| contains a html lang attribute which a page provides. It can
+// be empty string when a page doesn't provide it. |revised_code| is a value
+// modified by format error corrector.
+void ReportHtmlLang(const std::string& provided_code,
+                    const std::string& revised_code);
+
 // Called when CLD verifies Content-Language header.
 void ReportLanguageVerification(LanguageVerificationType type);
 
 // Called when the Translate Element library is ready.
 void ReportTimeToBeReady(double time_in_msec);
 
 // Called when the Translate Element library is loaded.
 void ReportTimeToLoad(double time_in_msec);
 
 // Called when a page translation is finished.
 void ReportTimeToTranslate(double time_in_msec);
 
 // Called when a translation is triggered.
 void ReportUserActionDuration(base::TimeTicks begin, base::TimeTicks end);
 
 #if defined(ENABLE_LANGUAGE_DETECTION)
 
 // Called when CLD detects page language.
 void ReportLanguageDetectionTime(base::TimeTicks begin, base::TimeTicks end);
 
 #endif  // defined(ENABLE_LANGUAGE_DETECTION)
 
 // Gets UMA name for an entry specified by |index|.
 const char* GetMetricsName(MetricsNameIndex index);
 
 }  // namespace TranslateHelperMetrics
 
 #endif  // CHROME_RENDERER_TRANSLATE_TRANSLATE_HELPER_METRICS_H_