Exclude extension settings strings for platforms that don't have extensions.

chrome/app/google_chrome_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 <!-- This file contains definitions of strings that are specific to
 Google Chrome. These strings will be translated for each locale that Google
 Chrome supports. -->
 
 <grit base_dir="." latest_public_release="0" current_release="1"
       source_lang_id="en" enc_check="möl">
   <outputs>
     <output filename="grit/google_chrome_strings.h" type="rc_header">
       <emit emit_type='prepend'></emit>
@@ skipping 677 matching lines @@
           Update
         </message>
       </if>
 
       <!-- Extension/App install prompt -->
       <message name="IDS_EXTENSION_INLINE_INSTALL_PROMPT_TITLE" desc="Titlebar of the extension or app inline installation prompt window">
         Add to Chrome
       </message>
 
       <!-- Extension installed bubble -->
-      <message name="IDS_EXTENSION_INSTALLED_HEADING" desc="First line in the content area of the extension installed bubble. Instructs that the extension was installed.">
-        <ph name="EXTENSION_NAME">$1<ex>Gmail Checker</ex></ph> has been added to Chrome.
-      </message>
+      <if expr="enable_extensions">
+        <message name="IDS_EXTENSION_INSTALLED_HEADING" desc="First line in the content area of the extension installed bubble. Instructs that the extension was installed.">
+          <ph name="EXTENSION_NAME">$1<ex>Gmail Checker</ex></ph> has been added to Chrome.
+        </message>
+        <message name="IDS_EXTENSION_INSTALLED_SIGNIN_PROMO_LINK" desc="The first part of the sign-in promo paragraph. This part will be converted to a link and will get more text appended to it (see IDS_EXTENSION_INSTALLED_SIGNIN_PROMO). Keep this text short.">
+          Sign in to Chrome
+        </message>
+      </if>
 
       <!-- chrome://settings/extensions page -->
       <message name="IDS_EXTENSIONS_INCOGNITO_WARNING" desc="Warns the user that Chrome cannot prevent extensions from recording history in incognito mode. Displayed in extensions management UI after an extension is selected to be run in incognito mode.">
         <ph name="BEGIN_BOLD">&lt;b&gt;</ph>Warning:<ph name="END_BOLD">&lt;/b&gt;</ph> Google Chrome cannot prevent extensions from recording your browsing history. To disable this extension in incognito mode, unselect this option.
       </message>
       <message name="IDS_EXTENSIONS_UNINSTALL" desc="The link for uninstalling extensions.">
         Remove from Chrome
       </message>
 
       <message name="IDS_EXTENSIONS_SUSPICIOUS_DISABLED_BODY" desc="Body of the dialog shown when suspicious extensions have been disabled">
@@ skipping 264 matching lines @@
       </message>
 
       <!-- ProcessSingleton -->
       <message name="IDS_PROFILE_IN_USE_LINUX" desc="Message shown when the browser cannot start because the profile is in use on a different host.">
         The profile appears to be in use by another Google Chrome process (<ph name="PROCESS_ID">$1<ex>12345</ex></ph>) on another computer (<ph name="HOST_NAME">$2<ex>example.com</ex></ph>).  Chrome has locked the profile so that it doesn't get corrupted.  If you are sure no other processes are using this profile, you can unlock the profile and relaunch Chrome.
       </message>
 
     </messages>
   </release>
 </grit>