MD Settings: Add "Show Google Now cards in the launcher" row in Search section.

chrome/app/settings_strings.grdp

 <?xml version="1.0" encoding="utf-8"?>
 <!-- Settings-specific strings (included from generated_resources.grd). -->
 <grit-part>
   <!-- About Page -->
   <message name="IDS_SETTINGS_ABOUT_PAGE_BROWSER_VERSION" desc="The text label describing the version of the browser, example: Version 57.0.2937.0 (Developer Build) unknown (64-bit)">
     Version <ph name="PRODUCT_VERSION">$1<ex>15.0.865.0</ex></ph> (<ph name="PRODUCT_CHANNEL">$2<ex>Developer Build</ex></ph>) <ph name="PRODUCT_MODIFIER">$3</ph> <ph name="PRODUCT_VERSION_BITS">$4</ph>
   </message>
   <if expr="chromeos">
     <message name="IDS_SETTINGS_ABOUT_PAGE_DETAILED_BUILD_INFO" desc="Label describing the section that shows detailed information about the current Chrome build.">
       Detailed build information
@@ skipping 1626 matching lines @@
   </message>
   <message name="IDS_SETTINGS_SEARCH_OK_GOOGLE_AUDIO_HISTORY_LABEL" desc="Text to display when the user has audio history enabled.">
     Voice and Audio Activity for <ph name="USER_EMAIL">$1<ex>joe@gmail.com</ex></ph>.
   </message>
   <message name="IDS_SETTINGS_SEARCH_OK_GOOGLE_AUDIO_HISTORY_SUBTEXT" desc="Subtext describing why audio history is enabled.">
     Enabled (required to use "Ok Google")
   </message>
   <message name="IDS_SETTINGS_SEARCH_OK_GOOGLE_RETRAIN" desc="Text for button to retrain the OK Google hotword voice model.">
     Retrain
   </message>
+  <message name="IDS_SETTINGS_SEARCH_ENABLE_GOOGLE_NOW" desc="Label for the checkbox which enables the Google Now in the launcher.">
+    Show Google Now cards in the launcher
+  </message>
 
   <!-- Search Engines Page -->
   <message name="IDS_SETTINGS_SEARCH_ENGINES" desc="Name of the settings page which manages search engines.">
     Search Engines
   </message>
   <message name="IDS_SETTINGS_SEARCH_ENGINES_ADD_SEARCH_ENGINE" desc="Title for a dialog that allows adding a new search engine.">
     Add search engine
   </message>
   <message name="IDS_SETTINGS_SEARCH_ENGINES_EDIT_SEARCH_ENGINE" desc="Title for a dialog that allows editing an existing search engine.">
     Edit search engine
@@ skipping 1081 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>