Translate: add UMA to measure duration time of infobar user action

chrome/renderer/translate/translate_helper_metrics.h

Index: chrome/renderer/translate/translate_helper_metrics.h
diff --git a/chrome/renderer/translate/translate_helper_metrics.h b/chrome/renderer/translate/translate_helper_metrics.h
index af23d82336cdfe60ca0b7f7ee63b46111031e62b..57abca3db0d09c635a3a8ad1ecea0e02cfe11ca6 100644
--- a/chrome/renderer/translate/translate_helper_metrics.h
+++ b/chrome/renderer/translate/translate_helper_metrics.h
@@ -20,6 +20,7 @@ enum MetricsNameIndex {
   UMA_TIME_TO_BE_READY,
   UMA_TIME_TO_LOAD,
   UMA_TIME_TO_TRANSLATE,
+  UMA_USER_ACTION_DURATION,
   UMA_MAX,
 };
 
@@ -62,6 +63,9 @@ 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.