Never unblock the last blocked language.

Bug: 902354, 872096
Change-Id: Ia2d51f0dd702fdc201a35118b19085fd38dc7678
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1475112Reviewed-by: anthonyvd <anthonyvd@chromium.org>
Reviewed-by: Moe Ahmadi <mahmadi@chromium.org>
Commit-Queue: Alexandre Frechette <frechette@chromium.org>
Cr-Commit-Position: refs/heads/master@{#638164}

components/translate/core/browser/translate_prefs.cc

@@ -462,8 +462,10 @@ void TranslatePrefs::UnblockLanguage(const std::string& input_language) {
 
   std::string translate_language = input_language;
   translate::ToTranslateLanguageSynonym(&translate_language);
-
-  RemoveValueFromBlacklist(kPrefTranslateBlockedLanguages, translate_language);
+  if (GetListSize(kPrefTranslateBlockedLanguages) > 1) {
+    RemoveValueFromBlacklist(kPrefTranslateBlockedLanguages,
+                             translate_language);
+  }
 }
 
 bool TranslatePrefs::IsSiteBlacklisted(const std::string& site) const {
@@ -547,7 +549,7 @@ void TranslatePrefs::RemoveLanguagePairFromWhitelist(
 }
 
 bool TranslatePrefs::HasBlockedLanguages() const {
-  return !IsListEmpty(kPrefTranslateBlockedLanguages);
+  return GetListSize(kPrefTranslateBlockedLanguages) != 0;
 }
 
 void TranslatePrefs::ClearBlockedLanguages() {
@@ -938,9 +940,9 @@ void TranslatePrefs::RemoveValueFromBlacklist(const char* pref_id,
   blacklist->Remove(string_value, nullptr);
 }
 
-bool TranslatePrefs::IsListEmpty(const char* pref_id) const {
+size_t TranslatePrefs::GetListSize(const char* pref_id) const {
   const base::ListValue* blacklist = prefs_->GetList(pref_id);
-  return (blacklist == nullptr || blacklist->empty());
+  return blacklist == nullptr ? 0 : blacklist->GetList().size();
 }
 
 bool TranslatePrefs::IsDictionaryEmpty(const char* pref_id) const {

components/translate/core/browser/translate_prefs.h

@@ -236,9 +236,6 @@ class TranslatePrefs {
   void RemoveLanguagePairFromWhitelist(const std::string& original_language,
                                        const std::string& target_language);
 
-  // Will return true if at least one language has been blacklisted.
-  bool HasBlockedLanguages() const;
-
   // Will return true if at least one site has been blacklisted.
   bool HasBlacklistedSites() const;
 
@@ -352,6 +349,9 @@ class TranslatePrefs {
   // Updates the language list of the language settings.
   void UpdateLanguageList(const std::vector<std::string>& languages);
 
+  // Will return true if at least one language has been blocked.
+  bool HasBlockedLanguages() const;
+
   // Merges two language sets to migrate to the language setting UI.
   static void CreateBlockedLanguages(
       std::vector<std::string>* blocked_languages,
@@ -361,12 +361,15 @@ class TranslatePrefs {
   void ClearBlockedLanguages();
   void ClearBlacklistedSites();
   void ClearWhitelistedLanguagePairs();
+
+  // |pref_id| is the name of a list pref.
   bool IsValueBlacklisted(const char* pref_id, const std::string& value) const;
   void BlacklistValue(const char* pref_id, const std::string& value);
   void RemoveValueFromBlacklist(const char* pref_id, const std::string& value);
   bool IsValueInList(const base::ListValue* list,
                      const std::string& value) const;
-  bool IsListEmpty(const char* pref_id) const;
+  size_t GetListSize(const char* pref_id) const;
+
   bool IsDictionaryEmpty(const char* pref_id) const;
   // Removes from the language list any language that isn't supported as an
   // Accept-Language (it's not in kAcceptLanguageList) if and only if there

components/translate/core/browser/translate_prefs_unittest.cc

@@ -391,6 +391,7 @@ TEST_F(TranslatePrefsTest, GetLanguageInfoList) {
 
 TEST_F(TranslatePrefsTest, BlockLanguage) {
   // `en` is a default blocked language, it should be present already.
+  ExpectBlockedLanguageListContent({"en"});
 
   // One language.
   translate_prefs_->BlockLanguage("fr-CA");
@@ -427,17 +428,26 @@ TEST_F(TranslatePrefsTest, BlockLanguage) {
 
 TEST_F(TranslatePrefsTest, UnblockLanguage) {
   // Language in the list.
+  // Should not unblock last language.
   translate_prefs_->UnblockLanguage("en-UK");
-  ExpectBlockedLanguageListContent({});
+  ExpectBlockedLanguageListContent({"en"});
 
-  // Language not in the list.
-  translate_prefs_->BlockLanguage("en-UK");
-  translate_prefs_->UnblockLanguage("es-AR");
+  // Language in the list but with different region.
+  // Should not unblock last language.
+  translate_prefs_->UnblockLanguage("en-AU");
   ExpectBlockedLanguageListContent({"en"});
 
+  // Language in the list.
+  translate_prefs_->ClearBlockedLanguages();
+  translate_prefs_->BlockLanguage("fr");
+  translate_prefs_->UnblockLanguage("en-UK");
+  ExpectBlockedLanguageListContent({"fr"});
+
   // Language in the list but with different region.
+  translate_prefs_->ClearBlockedLanguages();
+  translate_prefs_->BlockLanguage("fr");
   translate_prefs_->UnblockLanguage("en-AU");
-  ExpectBlockedLanguageListContent({});
+  ExpectBlockedLanguageListContent({"fr"});
 
   // Multiple languages.
   translate_prefs_->ClearBlockedLanguages();
@@ -519,6 +529,23 @@ TEST_F(TranslatePrefsTest, RemoveFromLanguageListRemovesRemainingUnsupported) {
   ExpectLanguagePrefs("");
 }
 
+TEST_F(TranslatePrefsTest, ResetEmptyBlockedLanguagesToDefaults) {
+  ExpectBlockedLanguageListContent({"en"});
+
+  translate_prefs_->ResetEmptyBlockedLanguagesToDefaults();
+  ExpectBlockedLanguageListContent({"en"});
+
+  translate_prefs_->BlockLanguage("fr");
+  translate_prefs_->ResetEmptyBlockedLanguagesToDefaults();
+  ExpectBlockedLanguageListContent({"en", "fr"});
+
+  prefs_->Set(TranslatePrefs::kPrefTranslateBlockedLanguages,
+              base::ListValue());
+  ExpectBlockedLanguageListContent({});
+  translate_prefs_->ResetEmptyBlockedLanguagesToDefaults();
+  ExpectBlockedLanguageListContent({"en"});
+}
+
 TEST_F(TranslatePrefsTest, RemoveFromLanguageListClearsRecentLanguage) {
   std::vector<std::string> languages;
 
@@ -931,7 +958,7 @@ TEST_F(TranslatePrefsTest, DefaultBlockedLanguages) {
   // default accept languages for Chrome (resource IDS_ACCEPT_LANGUAGES,
   // provided by components_locale_settings_en-US.pak), and
   // language::kFallbackInputMethodLocale for ChromeOS. For the tests, the
-  // resources are given by .
+  // resources match.
   std::vector<std::string> blocked_languages_expected = {"en"};
   ExpectBlockedLanguageListContent(blocked_languages_expected);
 }
@@ -968,5 +995,4 @@ TEST_F(TranslatePrefsTest, CanTranslateLanguage) {
   EXPECT_TRUE(translate_prefs_->CanTranslateLanguage(
       &translate_accept_languages, "en"));
 }
-
 }  // namespace translate