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

components/translate/core/browser/translate_prefs.h

Index: components/translate/core/browser/translate_prefs.h
diff --git a/components/translate/core/browser/translate_prefs.h b/components/translate/core/browser/translate_prefs.h
index 8c803a5e743deb63c5dcb75bb4cb395ea10a24f8..4887ef78a5c687e4d2d0ed651690ba013f8461ef 100644
--- a/components/translate/core/browser/translate_prefs.h
+++ b/components/translate/core/browser/translate_prefs.h
@@ -35,6 +35,13 @@ namespace translate {
 // Feature flag for "Translate UI 2016 Q2" project.
 extern const base::Feature kTranslateUI2016Q2;
 
+// The trail (study) name in finch study config.
+extern const char kTranslateUI2016Q2TrialName[];
+
+// The name of the parameter for the number of translation trigger the "Always
+// Translate" checkbox defaul to checked.

[groby-ooo-7-16, 2016/06/27 23:00:34]

nit:"default"

[ftang, 2016/06/28 05:01:46]

Done.

+extern const char kNumOfTranslationTriggerAlways[];

[groby-ooo-7-16, 2016/06/27 23:00:34]

The name is slightly unclear. Maybe kAlwaysTranslateOfferThreshold?

[ftang, 2016/06/28 05:01:46]

Done.

+
 class TranslateAcceptLanguages;
 
 // Allows updating denial times for a specific language while maintaining the
@@ -157,6 +164,10 @@ class TranslatePrefs {
                             const std::string& language);
   bool ShouldAutoTranslate(const std::string& original_language,
                            std::string* target_language);
+
+  // Decide to default check the Always Transalte setting.
+  bool ShouldAlwaysTranslateBeCheckedByDefault(const std::string& language);
+
   static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
   static void MigrateUserPrefs(PrefService* user_prefs,
                                const char* accept_languages_pref);