Fix a bug where users were able to remove a language used for displaying Chromium OS.

Users shoulnd't be able to remove such a language.
In the C++ version, we disabled the "Remove" button to prevent the action, but
in the DOMUI version, we'll show a warning instead, per suggestions from UX
designers.

BUG=chromium-os:5702
TEST=manually

Review URL: http://codereview.chromium.org/3122018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@56189 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 17 insertions, 1 deletions

diff --git a/chrome/app/generated_resources.grd b/chrome/app/generated_resources.grd
index cfae607..729828b 100644
--- a/chrome/app/generated_resources.grd
+++ b/chrome/app/generated_resources.grd
@@ -8657,6 +8657,10 @@ Keep your key file in a safe place. You will need it to create new versions of y
                desc="Warning invoked when the user tries to remove the last language">
         Please add another language before removing this one.
       </message>
+      <message name="IDS_OPTIONS_SETTINGS_LANGUAGES_THIS_LANGUAGE_IS_CURRENTLY_IN_USE"
+               desc="Warning invoked when the user tries to remove the language used for displaying Chrome OS">
+        This language is currently in use for displaying <ph name="PRODUCT_NAME">$1<ex>Chrome OS</ex></ph>.
+      </message>
       <message name="IDS_OPTIONS_SETTINGS_LANGUAGES_ADD_LANGUAGE_INSTRUCTIONS"
                desc="Explanatory message about how to add and order languages">
         Add languages and drag to order them based on your preference.
diff --git a/chrome/browser/chromeos/dom_ui/language_options_handler.cc b/chrome/browser/chromeos/dom_ui/language_options_handler.cc
index 11e006b..7037cea 100644
--- a/chrome/browser/chromeos/dom_ui/language_options_handler.cc
+++ b/chrome/browser/chromeos/dom_ui/language_options_handler.cc
@@ -83,6 +83,10 @@ void LanguageOptionsHandler::GetLocalizedValues(
           l10n_util::GetStringUTF16(IDS_PRODUCT_OS_NAME)));
   localized_strings->SetString("restart_required",
       l10n_util::GetStringUTF16(IDS_OPTIONS_RESTART_REQUIRED));
+  localized_strings->SetString("this_language_is_currently_in_use",
+      l10n_util::GetStringFUTF16(
+          IDS_OPTIONS_SETTINGS_LANGUAGES_THIS_LANGUAGE_IS_CURRENTLY_IN_USE,
+          l10n_util::GetStringUTF16(IDS_PRODUCT_OS_NAME)));
 
   // GetSupportedInputMethods() never return NULL.
   scoped_ptr<InputMethodDescriptors> descriptors(
diff --git a/chrome/browser/resources/options/chromeos_language_options.js b/chrome/browser/resources/options/chromeos_language_options.js
index e0cca3e..61a1fc4 100644
--- a/chrome/browser/resources/options/chromeos_language_options.js
+++ b/chrome/browser/resources/options/chromeos_language_options.js
@@ -390,13 +390,21 @@ cr.define('options', function() {
     handleRemoveButtonClick_: function(e) {
       var languageOptionsList = $('language-options-list');
       var languageCode = languageOptionsList.getSelectedLanguageCode();
-      // Disable input methods associated with |languageCode|.
+      // Don't allow removing the language if it's as UI language.
+      if (languageCode == templateData.currentUiLanguageCode) {
+        // TODO(satorux): Show the message in a nicer way. See above.
+        alert(localStrings.getString('this_language_is_currently_in_use'));
+        return;
+      }
+      // Don't allow removing the language if cerntain conditions are met.
+      // See removePreloadEnginesByLanguageCode_() for details.
       if (!this.removePreloadEnginesByLanguageCode_(languageCode)) {
         // TODO(satorux): Show the message in a nicer way once we get a mock
         // from UX. crosbug.com/5546.
         alert(localStrings.getString('please_add_another_language'));
         return;
       }
+      // Disable input methods associated with |languageCode|.
       languageOptionsList.removeSelectedLanguage();
     },