[OsSettingsLanguages] Update spellcheck pref when dictionary is empty

The logic in settings side is added in https://crrev.com/c/1600384.
Main logic is to turn off kSpellcheckEnable when spell check is off
for the 1 supported language.

This is equivalent to turning off kSpellcheckEnable when
hun_dictionaries is empty as it has similar origin to spellCheckEnable.
They both come from users' spellcheck dictionaries pref, forced and
blocked dictionaries list.

More background: http://go/cros-lang-settings-spell-check-migrate

Update the test in languages_page_test.js to better reflect users's
action.

Side effect:
Originally, when users turn off spell check for all languages, spell
check is left on. Now, when they turn the last one off, spell check is
off as well.

Related CL: https://crrev.com/c/2360093
Drive-by: Remove unused SetSingleLanguageDictionary function in test.

Bug: 1113439
Change-Id: Id8700c3b357da53e22e5f79420b163c8ef50b2d8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2390300Reviewed-by: Guillaume Jenkins <gujen@google.com>
Reviewed-by: Rouslan Solomakhin <rouslan@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: My Nguyen <myy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#805734}

chrome/browser/resources/settings/languages_page/languages_page.js

@@ -106,9 +106,6 @@ Polymer({
         return [];
       },
     },
-
-    /** @private {string|undefined} */
-    languageSyncedWithBrowserEnableSpellchecking_: String,
     // </if>
 
     /**
@@ -641,29 +638,12 @@ Polymer({
 
       // Hide list of spell check languages if there is only 1 language
       // and we don't need to display any errors for that language
+
+      // TODO(crbug/1124888): Make hideSpellCheckLanugages_ a computed property
       this.hideSpellCheckLanguages_ = !singleLanguage.isManaged &&
           singleLanguage.downloadDictionaryFailureCount === 0;
-
-      // Turn off spell check if spell check for the 1 remaining language is
-      // off
-      if (!singleLanguage.spellCheckEnabled) {
-        this.setPrefValue('browser.enable_spellchecking', false);
-        this.languageSyncedWithBrowserEnableSpellchecking_ =
-            singleLanguage.language.code;
-      }
-
-      // Undo the sync if spell check appeared as turned off for the language
-      // because a download was still in progress. This only occurs when
-      // Settings is loaded for the very first time and dictionaries have not
-      // been downloaded yet.
-      if (this.languageSyncedWithBrowserEnableSpellchecking_ ===
-              singleLanguage.language.code &&
-          singleLanguage.spellCheckEnabled) {
-        this.setPrefValue('browser.enable_spellchecking', true);
-      }
     } else {
       this.hideSpellCheckLanguages_ = false;
-      this.languageSyncedWithBrowserEnableSpellchecking_ = undefined;
     }
   },
 

chrome/browser/spellchecker/spellcheck_service.cc

@@ -829,8 +829,15 @@ void SpellcheckService::OnSpellCheckDictionariesChanged() {
 
   // If there are no hunspell dictionaries to load, then immediately let the
   // renderers know the new state.
-  if (hunspell_dictionaries_.empty())
+  if (hunspell_dictionaries_.empty()) {
+#if !defined(OS_MAC)
+    // Only update non-MacOS platform because basic spell check on Mac OS
+    // is controlled by OS and doesn't depend on users' dictionaries pref
+    user_prefs::UserPrefs::Get(context_)->SetBoolean(
+        spellcheck::prefs::kSpellCheckEnable, false);
+#endif  // !defined(OS_MAC)
     InitForAllRenderers();
+  }
 }
 
 void SpellcheckService::OnUseSpellingServiceChanged() {

chrome/browser/spellchecker/spellcheck_service_browsertest.cc

@@ -149,11 +149,6 @@ class SpellcheckServiceBrowserTest : public InProcessBrowserTest,
     spellcheck->OnCustomDictionaryChanged(change);
   }
 
-  void SetSingleLanguageDictionary(const std::string& single_dictionary) {
-    prefs_->SetString(spellcheck::prefs::kSpellCheckDictionary,
-                      single_dictionary);
-  }
-
   void SetMultiLingualDictionaries(const std::string& multiple_dictionaries) {
     base::ListValue dictionaries_value;
     dictionaries_value.AppendStrings(
@@ -335,6 +330,16 @@ IN_PROC_BROWSER_TEST_F(SpellcheckServiceBrowserTest,
       GetPrefs()->GetBoolean(spellcheck::prefs::kSpellCheckUseSpellingService));
 }
 
+#if !defined(OS_MAC)
+IN_PROC_BROWSER_TEST_F(SpellcheckServiceBrowserTest,
+                       DisableSpellcheckIfDictionaryIsEmpty) {
+  InitSpellcheck(true, "", "en-US");
+  SetMultiLingualDictionaries("");
+
+  EXPECT_FALSE(GetPrefs()->GetBoolean(spellcheck::prefs::kSpellCheckEnable));
+}
+#endif  // !defined(OS_MAC)
+
 // Removing a spellcheck language from accept languages should remove it from
 // spellcheck languages list as well.
 IN_PROC_BROWSER_TEST_F(SpellcheckServiceBrowserTest,

chrome/test/data/webui/settings/languages_page_tests.js

@@ -631,27 +631,34 @@ suite('languages page', function() {
 
       const list = languagesPage.$.spellCheckLanguagesList;
       assertFalse(list.hidden);
+      assertTrue(languagesPage.$$('#enableSpellcheckingToggle').checked);
+      assertDeepEquals(
+          ['en-US'], languageHelper.getPref('spellcheck.dictionaries').value);
 
-      languageHelper.setPrefValue('intl.accept_languages', 'en-US');
-      if (isChromeOS) {
-        languageHelper.setPrefValue(
-            'settings.language.preferred_languages', 'en-US');
-      }
+      // Update supported languages to just 1 language should hide list.
+      languageHelper.setPrefValue(languagesPref, 'en-US');
+      flush();
+      assertTrue(list.hidden);
+
+      // Disable spell check should keep list hidden and remove the single
+      // language from dictionaries.
+      languagesPage.$$('#enableSpellcheckingToggle').click();
+      flush();
 
-      // Update supported languages to just 1 language English with spell
-      // check disabled for that language
-      languageHelper.setPrefValue('spellcheck.dictionaries', []);
       assertTrue(list.hidden);
-      assertFalse(languageHelper.getPref('browser.enable_spellchecking').value);
+      assertFalse(languagesPage.$$('#enableSpellcheckingToggle').checked);
+      assertDeepEquals(
+          [], languageHelper.getPref('spellcheck.dictionaries').value);
+
+      // Enable spell check should keep list hidden and add the single language
+      // to dictionaries.
+      languagesPage.$$('#enableSpellcheckingToggle').click();
+      flush();
 
-      // Update supported languages to just 1 language English that finished
-      // downloading and is now ready
-      languageHelper.setPrefValue('spellcheck.dictionaries', ['en-US']);
-      languageHelper.set('languages.enabled.0.downloadDictionaryStatus', {
-        isReady: true,
-      });
       assertTrue(list.hidden);
-      assertTrue(languageHelper.getPref('browser.enable_spellchecking').value);
+      assertTrue(languagesPage.$$('#enableSpellcheckingToggle').checked);
+      assertDeepEquals(
+          ['en-US'], languageHelper.getPref('spellcheck.dictionaries').value);
     });
 
     test('no supported languages', () => {