add experimental param to control the triggering threshold to default Always Translate checked

components/translate/core/browser/translate_prefs.h

 // Copyright 2014 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 COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_PREFS_H_
 #define COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_PREFS_H_
 
 #include <stddef.h>
 
 #include <string>
@@ skipping 17 matching lines @@
 
 namespace user_prefs {
 class PrefRegistrySyncable;
 }
 
 namespace translate {
 
 // Feature flag for "Translate UI 2016 Q2" project.
 extern const base::Feature kTranslateUI2016Q2;
 
+// The trial (study) name in finch study config.
+extern const char kTranslateUI2016Q2TrialName[];
+
+// The name of the parameter for the number of translations, after which the
+// "Always Translate" checkbox default to checked.
+extern const char kAlwaysTranslateOfferThreshold[];
+
 class TranslateAcceptLanguages;
 
 // Allows updating denial times for a specific language while maintaining the
 // maximum list size and ensuring PrefObservers are notified of change values.
 class DenialTimeUpdate {
  public:
   DenialTimeUpdate(PrefService* prefs,
                    const std::string& language,
                    size_t max_denial_count);
   ~DenialTimeUpdate();
@@ skipping 102 matching lines @@
   // Gets the language list of the language settings.
   void GetLanguageList(std::vector<std::string>* languages) const;
 
   // Updates the language list of the language settings.
   void UpdateLanguageList(const std::vector<std::string>& languages);
 
   bool CanTranslateLanguage(TranslateAcceptLanguages* accept_languages,
                             const std::string& language);
   bool ShouldAutoTranslate(const std::string& original_language,
                            std::string* target_language);
+
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
   static void MigrateUserPrefs(PrefService* user_prefs,
                                const char* accept_languages_pref);
 
  private:
   friend class TranslatePrefsTest;
 
   // Merges two language sets to migrate to the language setting UI.
   static void CreateBlockedLanguages(
       std::vector<std::string>* blocked_languages,
@@ skipping 30 matching lines @@
   PrefService* prefs_;  // Weak.
 
   std::string country_;  // The country the app runs in.
 
   DISALLOW_COPY_AND_ASSIGN(TranslatePrefs);
 };
 
 }  // namespace translate
 
 #endif  // COMPONENTS_TRANSLATE_CORE_BROWSER_TRANSLATE_PREFS_H_