Update test "LanguageOptionsWebUITest.reselectUILocale"

Current implementation assumes that current UI language is the first language
on the list. It works now but might break in the future.
To avoid that we should select current UI language on left pane
before making any checks.

R=dbeam@chromium.org

Review URL: https://codereview.chromium.org/399353006

Cr-Commit-Position: refs/heads/master@{#288439}
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@288439 0039d316-1c4b-4281-b951-d872f2087c98

chrome/browser/ui/webui/options/language_options_browsertest.js

@@ -27,6 +27,7 @@ GEN('#if defined(OS_WIN) || defined(OS_CHROMEOS)');
 // or a [ Display Chrome in this language ] button.
 TEST_F('LanguageOptionsWebUITest', 'reselectUILocale', function() {
   var currentLang = loadTimeData.getString('currentUiLanguageCode');
+  $('language-options-list').selectLanguageByCode(currentLang);
   LanguageOptions.uiLanguageSaved(currentLang);
 
   expectTrue($('language-options-ui-language-button').hidden);