Removed logic for translate UI language override experiment.

The experiment has been disabled, so its logic is no longer required. Removing
it will simplify upcoming improvements to user language modeling.

Bug: 759432
Change-Id: I2847d37c00b7d32641260f5f5ebad2f7ad4eba0a
Reviewed-on: https://chromium-review.googlesource.com/637434
Commit-Queue: Michael Martis <martis@chromium.org>
Reviewed-by: Rachel Blum <groby@chromium.org>
Cr-Commit-Position: refs/heads/master@{#499147}

components/translate/core/browser/BUILD.gn

@@ -20,8 +20,6 @@ static_library("browser") {
     "translate_error_details.h",
     "translate_event_details.cc",
     "translate_event_details.h",
-    "translate_experiment.cc",
-    "translate_experiment.h",
     "translate_language_list.cc",
     "translate_language_list.h",
     "translate_manager.cc",
@@ -96,7 +94,6 @@ source_set("unit_tests") {
     "mock_translate_ranker.h",
     "translate_accept_languages_unittest.cc",
     "translate_browser_metrics_unittest.cc",
-    "translate_experiment_unittest.cc",
     "translate_language_list_unittest.cc",
     "translate_manager_unittest.cc",
     "translate_prefs_unittest.cc",

components/translate/core/browser/translate_manager.cc

@@ -26,7 +26,6 @@
 #include "components/translate/core/browser/translate_download_manager.h"
 #include "components/translate/core/browser/translate_driver.h"
 #include "components/translate/core/browser/translate_error_details.h"
-#include "components/translate/core/browser/translate_experiment.h"
 #include "components/translate/core/browser/translate_language_list.h"
 #include "components/translate/core/browser/translate_prefs.h"
 #include "components/translate/core/browser/translate_ranker.h"
@@ -483,24 +482,16 @@ void TranslateManager::OnTranslateScriptFetchComplete(
 
 // static
 std::string TranslateManager::GetTargetLanguage(const TranslatePrefs* prefs) {
-  std::string language;
-
-  // Get the override UI language.
-  TranslateExperiment::OverrideUiLanguage(prefs->GetCountry(), &language);
-
-  // If there are no override.
-  if (language.empty()) {
-    // Get the language from ULP.
-    language = TranslateManager::GetTargetLanguageFromULP(prefs);
-    if (!language.empty())
-      return language;
-
-    // Get the browser's user interface language.
-    language = TranslateDownloadManager::GetLanguageCode(
-        TranslateDownloadManager::GetInstance()->application_locale());
-    // Map 'he', 'nb', 'fil' back to 'iw', 'no', 'tl'
-    translate::ToTranslateLanguageSynonym(&language);
-  }
+  // Get target language from ULP if the ULP experiment is enabled.
+  std::string language = TranslateManager::GetTargetLanguageFromULP(prefs);
+  if (!language.empty())
+    return language;
+
+  // Get the browser's user interface language.
+  language = TranslateDownloadManager::GetLanguageCode(
+      TranslateDownloadManager::GetInstance()->application_locale());
+  // Map 'he', 'nb', 'fil' back to 'iw', 'no', 'tl'
+  translate::ToTranslateLanguageSynonym(&language);
   if (TranslateDownloadManager::IsSupportedLanguage(language))
     return language;
 
@@ -513,6 +504,7 @@ std::string TranslateManager::GetTargetLanguage(const TranslatePrefs* prefs) {
     if (TranslateDownloadManager::IsSupportedLanguage(lang_code))
       return lang_code;
   }
+
   return std::string();
 }
 

components/translate/core/browser/translate_prefs.cc

@@ -18,7 +18,6 @@
 #include "components/prefs/scoped_user_pref_update.h"
 #include "components/translate/core/browser/translate_accept_languages.h"
 #include "components/translate/core/browser/translate_download_manager.h"
-#include "components/translate/core/browser/translate_experiment.h"
 #include "components/translate/core/browser/translate_pref_names.h"
 #include "components/translate/core/common/translate_util.h"
 
@@ -491,25 +490,15 @@ bool TranslatePrefs::CanTranslateLanguage(
       TranslateAcceptLanguages::CanBeAcceptLanguage(language);
   bool is_accept_language = accept_languages->IsAcceptLanguage(language);
 
-  // For the translate language experiment, blocklists can be overridden.
-  const std::string& app_locale =
-      TranslateDownloadManager::GetInstance()->application_locale();
-  std::string ui_lang = TranslateDownloadManager::GetLanguageCode(app_locale);
-  if (TranslateExperiment::ShouldOverrideBlocking(ui_lang, language))
-    return true;
-
   // Don't translate any user black-listed languages. Checking
   // |is_accept_language| is necessary because if the user eliminates the
   // language from the preference, it is natural to forget whether or not
   // the language should be translated. Checking |cannot_be_accept_language|
   // is also necessary because some minor languages can't be selected in the
   // language preference even though the language is available in Translate
   // server.
-  if (IsBlockedLanguage(language) &&
-      (is_accept_language || !can_be_accept_language))
-    return false;
-
-  return true;
+  return !IsBlockedLanguage(language) ||
+         (!is_accept_language && can_be_accept_language);
 }
 
 bool TranslatePrefs::ShouldAutoTranslate(const std::string& original_language,

components/translate/core/browser/translate_prefs.h

@@ -102,7 +102,7 @@ class TranslatePrefs {
   bool IsEnabled() const;
 
   // Sets the country that the application is run in. Determined by the
-  // VariationsService, can be left empty. Used by TranslateExperiment.
+  // VariationsService, can be left empty. Used by the TranslateRanker.
   void SetCountry(const std::string& country);
   std::string GetCountry() const;