Translate: adopt html lang attribute if valid value is provided

chrome/renderer/translate/translate_helper_metrics.cc

 // 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.
 
 #include "chrome/renderer/translate/translate_helper_metrics.h"
 
 #include "base/basictypes.h"
 #include "base/metrics/histogram.h"
 
 namespace {
 
 // Constant string values to indicate UMA names. All entries should have
 // a corresponding index in MetricsNameIndex and an entry in |kMetricsEntries|.
 const char kRenderer4LanguageDetection[] = "Renderer4.LanguageDetection";
 const char kTranslateContentLanguage[] = "Translate.ContentLanguage";
+const char kTranslateHtmlLang[] = "Translate.HtmlLang";
 const char kTranslateLanguageVerification[] = "Translate.LanguageVerification";
 const char kTranslateTimeToBeReady[] = "Translate.TimeToBeReady";
 const char kTranslateTimeToLoad[] = "Translate.TimeToLoad";
 const char kTranslateTimeToTranslate[] = "Translate.TimeToTranslate";
 const char kTranslateUserActionDuration[] = "Translate.UserActionDuration";
 
 struct MetricsEntry {
   TranslateHelperMetrics::MetricsNameIndex index;
   const char* const name;
 };
 
 // This entry table should be updated when new UMA items are added.
 const MetricsEntry kMetricsEntries[] = {
   { TranslateHelperMetrics::UMA_LANGUAGE_DETECTION,
     kRenderer4LanguageDetection },
   { TranslateHelperMetrics::UMA_CONTENT_LANGUAGE,
     kTranslateContentLanguage },
+  { TranslateHelperMetrics::UMA_HTML_LANG,
+    kTranslateHtmlLang },
   { TranslateHelperMetrics::UMA_LANGUAGE_VERIFICATION,
     kTranslateLanguageVerification },
   { TranslateHelperMetrics::UMA_TIME_TO_BE_READY,
     kTranslateTimeToBeReady },
   { TranslateHelperMetrics::UMA_TIME_TO_LOAD,
     kTranslateTimeToLoad },
   { TranslateHelperMetrics::UMA_TIME_TO_TRANSLATE,
     kTranslateTimeToTranslate },
   { TranslateHelperMetrics::UMA_USER_ACTION_DURATION,
     kTranslateUserActionDuration },
 };
 
 COMPILE_ASSERT(arraysize(kMetricsEntries) == TranslateHelperMetrics::UMA_MAX,
                arraysize_of_kMetricsEntries_should_be_UMA_MAX);
 
+void ReportLanguageCheck(const char* metric_name,
+                         const std::string& provided_code,
+                         const std::string& revised_code) {
+  if (provided_code.empty()) {
+    UMA_HISTOGRAM_ENUMERATION(metric_name,

[Ilya Sherman, 2013/05/22 20:26:17]

This won't work as you want it to -- the histogram name that's passed to an
UMA_HISTOGRAM_ macro needs to be a runtime constant, as the macro defines a
static local variable.  I'd recommend defining a helper function that takes the
|provided_code| and |revised_code| and returns the metric (NOT_PROVIDED, VALID,
or INVALID) that should be logged; and invoking this helper function where you
are currently calling ReportLanguageCheck.

[Takashi Toyoshima, 2013/05/23 00:37:14]

Thanks.
As you said, unit_tests fails on this.
(Sorry, I should notice that before asking on review)
I'll follow your suggestion.

+                              TranslateHelperMetrics::LANGUAGE_NOT_PROVIDED,
+                              TranslateHelperMetrics::LANGUAGE_MAX);
+  } else if (provided_code == revised_code) {
+    UMA_HISTOGRAM_ENUMERATION(metric_name,
+                              TranslateHelperMetrics::LANGUAGE_VALID,
+                              TranslateHelperMetrics::LANGUAGE_MAX);
+  } else {
+    UMA_HISTOGRAM_ENUMERATION(metric_name,
+                              TranslateHelperMetrics::LANGUAGE_INVALID,
+                              TranslateHelperMetrics::LANGUAGE_MAX);
+  }
+}
+
 }  // namespace
 
 namespace TranslateHelperMetrics {
 
 void ReportContentLanguage(const std::string& provided_code,
                            const std::string& revised_code) {
-  if (provided_code.empty()) {
-    UMA_HISTOGRAM_ENUMERATION(kTranslateContentLanguage,
-                              CONTENT_LANGUAGE_NOT_PROVIDED,
-                              CONTENT_LANGUAGE_MAX);
-  } else if (provided_code == revised_code) {
-    UMA_HISTOGRAM_ENUMERATION(kTranslateContentLanguage,
-                              CONTENT_LANGUAGE_VALID,
-                              CONTENT_LANGUAGE_MAX);
-  } else {
-    UMA_HISTOGRAM_ENUMERATION(kTranslateContentLanguage,
-                              CONTENT_LANGUAGE_INVALID,
-                              CONTENT_LANGUAGE_MAX);
-  }
+  ReportLanguageCheck(kTranslateContentLanguage, provided_code, revised_code);
+}
+
+void ReportHtmlLang(const std::string& provided_code,
+                    const std::string& revised_code) {
+  ReportLanguageCheck(kTranslateHtmlLang, provided_code, revised_code);
 }
 
 void ReportLanguageVerification(LanguageVerificationType type) {
   UMA_HISTOGRAM_ENUMERATION(kTranslateLanguageVerification,
                             type,
                             LANGUAGE_VERIFICATION_MAX);
 }
 
 void ReportTimeToBeReady(double time_in_msec) {
   UMA_HISTOGRAM_MEDIUM_TIMES(
@@ skipping 28 matching lines @@
 const char* GetMetricsName(MetricsNameIndex index) {
   for (size_t i = 0; i < arraysize(kMetricsEntries); ++i) {
     if (kMetricsEntries[i].index == index)
       return kMetricsEntries[i].name;
   }
   NOTREACHED();
   return NULL;
 }
 
 } // namespace TranslateHelperMetrics