Change ::shadow to * /deep/ to stop relying on implementation bug.

ui/webui/resources/js/i18n_template_no_process.js

 // Copyright (c) 2012 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.
 
 /** @typedef {Document|DocumentFragment|Element} */
 var ProcessingRoot;
 
 /**
  * @fileoverview This is a simple template engine inspired by JsTemplates
  * optimized for i18n.
@@ skipping 106 matching lines @@
         }
       });
     }
   };
 
   var prefixes = [''];
 
   // Only look through shadow DOM when it's supported. As of April 2015, iOS
   // Chrome doesn't support shadow DOM.
   if (Element.prototype.createShadowRoot)
-    prefixes.push('::shadow ');
+    prefixes.push('* /deep/ ');
 
   var attributeNames = Object.keys(handlers);
   var selector = prefixes.map(function(prefix) {
     return prefix + '[' + attributeNames.join('], ' + prefix + '[') + ']';
   }).join(', ');
 
   /**
    * Processes a DOM tree using a |data| source to populate template values.
    * @param {!ProcessingRoot} root The root of the DOM tree to process.
    * @param {!LoadTimeData} data The data to draw from.
@@ skipping 64 matching lines @@
       var attribute = element.getAttribute(name);
       if (attribute != null)
         handlers[name](element, attribute, data, visited);
     }
   }
 
   return {
     process: process
   };
 }());