[ios] Pass more --jscomp_error switches to the closure Compiler.

components/translate/ios/browser/resources/language_detection.js

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-__gCrWeb['languageDetection'] = {};
+/**
+ * @fileoverview Installs Language Detection management functions on the
+ * __gCrWeb object.
+ *
+ * TODO(crbug.com/659442): Enable checkTypes error for this file.
+ * @suppress {checkTypes}
+ */
 
+__gCrWeb.languageDetection = {};
+
+// Store languageDetection namespace object in a global __gCrWeb object
+// referenced by a string, so it does not get renamed by closure compiler during
+// the minification.
+__gCrWeb['languageDetection'] = __gCrWeb.languageDetection;
 
 (function() {
 /**
  * The cache of the text content that was extracted from the page
  */
 __gCrWeb.languageDetection.bufferedTextContent = null;
 
 /**
  * The number of active requests that have populated the cache. This is
  * incremented every time a call to |__gCrWeb.languageDetection.detectLanguage|
@@ skipping 138 matching lines @@
 __gCrWeb.languageDetection['retrieveBufferedTextContent'] = function() {
   var textContent = __gCrWeb.languageDetection.bufferedTextContent;
   __gCrWeb.languageDetection.activeRequests -= 1;
   if (__gCrWeb.languageDetection.activeRequests == 0) {
     __gCrWeb.languageDetection.bufferedTextContent = null;
   }
   return textContent;
 }
 
 }())  // End of anonymous function.