MD Settings: add empty list message for spell-check edit page.

chrome/app/settings_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Settings-specific strings (included from generated_resources.grd). -->
 <grit-part>
   <!-- Main Page -->
   <if expr="chromeos">
     <message name="IDS_SETTINGS_SECONDARY_USER_BANNER" desc="Banner displayed in settings page when the user is secondary in a multi-profile session.">
       Some settings belonging to <ph name="PRIMARY_EMAIL">$1<ex>john@google.com</ex></ph> are being shared with you. These settings only affect your account when using multiple sign-in.
     </message>
   </if>
 
@@ skipping 1513 matching lines @@
     </message>
     <message name="IDS_SETTINGS_LANGUAGES_ADD_DICTIONARY_WORD" desc="Label for the text input used to add a new word to the custom spell check dictionary.">
       Add a new word
     </message>
     <message name="IDS_SETTINGS_LANGUAGES_ADD_DICTIONARY_WORD_BUTTON" desc="Button next to the 'add word' text input used to add the word typed by the user to the custom spell check dictionary.">
       Add word
     </message>
     <message name="IDS_SETTINGS_LANGUAGES_DICTIONARY_WORDS" desc="Header for the list of custom dictionary words used for spell check.">
       Custom words
     </message>
+    <message name="IDS_SETTINGS_LANGUAGES_DICTIONARY_WORDS_NONE" desc="Placeholder that is shown when there are no custom words in the list of saved custom words dictionary.">
+      No custom words were found
+    </message>
   </if>
 
   <!-- Privacy Page -->
   <message name="IDS_SETTINGS_PRIVACY" desc="Name of the settings page which allows users to modify privacy and security settings.">
     Privacy and security
   </message>
   <message name="IDS_SETTINGS_LINKDOCTOR_PREF" desc="The documentation string of the 'Use Link Doctor' preference to help with navigation errors.">
     Use a web service to help resolve navigation errors
   </message>
   <if expr="chromeos">
@@ skipping 1334 matching lines @@
       System
     </message>
     <message name="IDS_SETTINGS_SYSTEM_HARDWARE_ACCELERATION_LABEL" desc="Label for the checkbox that forces Chrome to render via hardware acceleration (GPU) when available.">
       Use hardware acceleration when available
     </message>
     <message name="IDS_SETTINGS_SYSTEM_PROXY_SETTINGS_BUTTON" desc="Text for the button that changes a user's network proxy settings.">
       Change proxy settings
     </message>
   </if>
 </grit-part>