MD Settings: OnStartup, implementing "Edit" functionality.

chrome/app/settings_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Settings-specific strings (included from generated_resources.grd). -->
 <grit-part>
   <!-- Policy Indicators -->
   <message name="IDS_SETTINGS_CONTROLLED_SETTING_EXTENSION" desc="Text displayed in the controlled settings indicator tooltip when a setting's value is enforced by an extension.">
     This setting is controlled by extension <ph name="NAME">$1<ex>Settings Extension</ex></ph>
   </message>
 
   <!-- Accessibility Page -->
   <message name="IDS_SETTINGS_ACCESSIBILITY" desc="Name of the settings page which displays accessibility preferences.">
@@ skipping 555 matching lines @@
   </message>
   <message name="IDS_SETTINGS_ON_STARTUP_OPEN_SPECIFIC" desc="Radio button option to open a specific set of pages.">
     Open a specific page or set of pages
   </message>
   <message name="IDS_SETTINGS_ON_STARTUP_USE_CURRENT" desc="Button to use current pages.">
     Use current pages
   </message>
   <message name="IDS_SETTINGS_ON_STARTUP_ADD_NEW_PAGE" desc="Entry prompt to add a new page.">
     Add a new page
   </message>
+  <message name="IDS_SETTINGS_ON_STARTUP_EDIT_PAGE" desc="Title of the dialog that allows the user to edit an existing startup page.">
+   Edit page
+  </message>
   <message name="IDS_SETTINGS_ON_STARTUP_SITE_URL" desc="Prompt to add a new page.">
     Site URL
   </message>
   <message name="IDS_SETTINGS_ON_STARTUP_REMOVE" desc="Text displayed on a menu button allowing the user to remove a URL from the list of startup URLs.">
     Remove
   </message>
+  <message name="IDS_SETTINGS_ON_STARTUP_EDIT" desc="Text displayed on a menu button allowing the user to edit a URL from the list of startup URLs.">
+    Edit
+  </message>
 
   <!-- Languages Page -->
   <message name="IDS_SETTINGS_LANGUAGES_PAGE_TITLE" desc="Name of the settings page which displays language preferences.">
     Languages
   </message>
   <message name="IDS_SETTINGS_LANGUAGES_LANGUAGES_LIST_TITLE" desc="Title for the currently used language in the header for the collapsible list of languages.">
     Language
   </message>
   <message name="IDS_SETTINGS_LANGUAGES_LANGUAGES_MANAGE" desc="Button under the list of enabled languages which opens a sub-page that lets the user enable or disable languages.">
     Manage languages
@@ skipping 624 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>