If shadow DOM is not supported, search for i18n attributes without using the /deep/ selector.

ui/webui/resources/js/i18n_template_no_process.js

Index: ui/webui/resources/js/i18n_template_no_process.js
diff --git a/ui/webui/resources/js/i18n_template_no_process.js b/ui/webui/resources/js/i18n_template_no_process.js
index 9c951eeb89c084d8a43a472725f58f1d76433f47..6f1f71551569c037779a2938645f90ee6fd039c7 100644
--- a/ui/webui/resources/js/i18n_template_no_process.js
+++ b/ui/webui/resources/js/i18n_template_no_process.js
@@ -111,7 +111,14 @@ var i18nTemplate = (function() {
   };
 
   var attributeNames = Object.keys(handlers);
-  var selector = 'html /deep/ [' + attributeNames.join('],[') + ']';
+  // Chrome for iOS must use Apple's UIWebView, which (as of April 2015) does
+  // not have native shadow DOM support. If shadow DOM is supported (or
+  // polyfilled), search for i18n attributes using the /deep/ selector;
+  // otherwise, do not attempt to search within the shadow DOM.
+  var selector =
+      (window.document.body && window.document.body.createShadowRoot) ?
+      'html /deep/ [' + attributeNames.join('],[') + ']' :

[Dan Beam, 2015/06/23 23:33:12]

so this is whining in the console now about /deep/ being deprecated:

  /deep/ combinator is deprecated. See
https://www.chromestatus.com/features/6750456638341120 for more details.

+      '[' + attributeNames.join('],[') + ']';
 
   /**
    * Processes a DOM tree with the {@code dictionary} map.