[MD Settings] Add title to show/hide password button.

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 403 matching lines @@
   </message>
   <message name="IDS_SETTINGS_PASSWORD_DONE" desc="Label for a button that dismisses the password details dialog.">
     Done
   </message>
   <message name="IDS_SETTINGS_PASSWORD_REMOVE" desc="Label for a context menu item that removes the selected password." meaning="Remove selected password.">
     Remove
   </message>
   <message name="IDS_SETTINGS_PASSWORD_SEARCH" desc="Placeholder/label for the text input field that allows a user to filter saved passwords.">
     Search passwords
   </message>
+  <message name="IDS_SETTINGS_PASSWORD_SHOW" desc="A tool tip on a button that reveals the saved password.">
+    Show password
+  </message>
+  <message name="IDS_SETTINGS_PASSWORD_HIDE" desc="A tool tip on a button that hides the saved password that is being shown.">
+    Hide password
+  </message>
   <message name="IDS_SETTINGS_PASSWORDS_VIEW_DETAILS_TITLE" desc="Title for the dialog that shows password details. This dialog lets a user see a saved password and copy the username.">
     Saved password details
   </message>
   <message name="IDS_SETTINGS_PASSWORD_VIEW_DETAILS" desc="Label for a context menu item that shows a dialog with details for the selected password.">
     View details
   </message>
   <message name="IDS_SETTINGS_PASSWORDS_WEBSITE" desc="Label for the website a password is for when editing a password.">
     Website
   </message>
   <message name="IDS_SETTINGS_PASSWORDS_USERNAME" desc="Label for the saved username when editing a password.">
@@ skipping 2429 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>