Add deprecation warning banner to App Launcher on Mac.

chrome/app/chromium_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 <!-- This file contains definitions of strings that are distribution specific.
 If you update this file, be sure also to update google_chrome_strings.grd. -->
 
 <grit base_dir="." latest_public_release="0" current_release="1"
       source_lang_id="en" enc_check="möl">
   <outputs>
     <output filename="grit/chromium_strings.h" type="rc_header">
       <emit emit_type='prepend'></emit>
     </output>
@@ skipping 860 matching lines @@
         <if expr="not use_titlecase">
           <message name="IDS_APP_LIST_EXTENSIONS_UNINSTALL" desc="Title text for the context menu item of a non-platform-app app list item that removes the app.">
             Remove from Chromium...
           </message>
         </if>
         <if expr="use_titlecase">
           <message name="IDS_APP_LIST_EXTENSIONS_UNINSTALL" desc="In Title Case: Title text for the context menu item of a non-platform-app app list item that removes the app.">
             Remove From Chromium...
           </message>
         </if>
+        <if expr="not chromeos">
+          <message name="IDS_APP_LIST_MESSAGE_TITLE" desc="Title given to the message displayed in the app launcher to say it is going away">
+            The Chromium App Launcher is going away
+          </message>
+          <message name="IDS_APP_LIST_MESSAGE_TEXT" desc="The message body text displayed in the app launcher to say it is going away">
+            Use the <ph name="APPS_ICON_IMAGE">$1<ex>[inline-image] Apps</ex></ph> shortcut in the Chromium bookmarks bar to continue accessing your apps.

[Matt Giuca, 2016/03/22 03:28:05]

I think you can drop "[inline-image]". The translator doesn't need to know that
and it might just confuse.

[tapted, 2016/03/22 04:58:14]

Done.

+          </message>
+        </if>
       </if>
 
       <!-- App shortcuts -->
       <message name="IDS_APP_SHORTCUTS_SUBDIR_NAME" desc="Name for the Chromium Apps Start Menu folder name.">
         Chromium Apps
       </message>
       <message name="IDS_APP_SHORTCUTS_SUBDIR_NAME_CANARY" desc="Name for the Chrome Apps Start Menu folder name.">
         Chromium Apps
       </message>
 
@@ skipping 275 matching lines @@
         </message>
         <message name="IDS_METRO_FLOW_LOGO_STRING_ALT"
                  desc="Alt text for the faded Chrome logo image.">
           Chromium logo
         </message>
       </if>
 
     </messages>
   </release>
 </grit>