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

chrome/renderer/translate/translate_helper.h

 // Copyright (c) 2011 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_H_
 #define CHROME_RENDERER_TRANSLATE_TRANSLATE_HELPER_H_
 
 #include <string>
 
 #include "base/gtest_prod_util.h"
@@ skipping 133 matching lines @@
   // Convenience method to access the main frame.  Can return NULL, typically
   // if the page is being closed.
   WebKit::WebFrame* GetMainFrame();
 
   // The states associated with the current translation.
   bool translation_pending_;
   int page_id_;
   std::string source_lang_;
   std::string target_lang_;
 
+  // Time when a page langauge is determined. This is used to know a duration
+  // time from showing infobar to requesting translation.
+  base::TimeTicks language_determined_time_;
+
   // Method factory used to make calls to TranslatePageImpl.
   base::WeakPtrFactory<TranslateHelper> weak_method_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(TranslateHelper);
 };
 
 #endif  // CHROME_RENDERER_TRANSLATE_TRANSLATE_HELPER_H_