Settings: Fall back to language only when locale is not found.

Navigator.language can return either a language only ('en') or a full
locale ('en-US'). If a locale is not found ('ru-RU'), then fall back to
using only the language ('ru').

Bug: 922088
Change-Id: I215071e55a9a01a97348491603a4bdabe739ff87
Reviewed-on: https://chromium-review.googlesource.com/c/1460479
Reviewed-by: Esmael El-Moslimany <aee@chromium.org>
Commit-Queue: Hector Carmona <hcarmona@chromium.org>
Cr-Commit-Position: refs/heads/master@{#630493}

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

@@ -986,7 +986,10 @@ Polymer({
    * @return {!chrome.languageSettingsPrivate.Language|undefined}
    */
   getLanguage: function(languageCode) {
-    return this.supportedLanguageMap_.get(languageCode);
+    // If a languageCode is not found, try language without location.
+    return this.supportedLanguageMap_.get(languageCode) ||
+        this.supportedLanguageMap_.get(
+            this.getLanguageCodeWithoutRegion(languageCode));
   },
 
   /**