Remove toggle button code from Tab Strip.

ios/chrome/app/strings/ios_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 
 <!--
 This file contains definition of resources that will be translated for each
 locale.  The strings in this file are specific to iOS.
 -->
 
 <grit base_dir="." latest_public_release="0" current_release="1"
       output_all_resource_defines="false" source_lang_id="en" enc_check="möl">
   <outputs>
@@ skipping 1278 matching lines @@
       </message>
       <message name="IDS_IOS_SPOTLIGHT_KEYWORD_THREE" desc="Keyword used in Spotlight that will be linked to the Chrome App. [iOS only]">
         Private
       </message>
       <message name="IDS_IOS_SPOTLIGHT_KEYWORD_TWO" desc="Keyword used in Spotlight that will be linked to the Chrome App. [iOS only]">
         Internet
       </message>
       <message name="IDS_IOS_SUGGESTIONS_DONE" desc="Label of the navigation bar button to close the view.">
         Done
       </message>
-      <message name="IDS_IOS_SWITCH_BROWSER_MODE_ENTER_INCOGNITO" desc="The accessibility label of the switch browser mode button to enter the Incognito mode [iOS only]">
-        Enter Incognito Mode
-      </message>
-      <message name="IDS_IOS_SWITCH_BROWSER_MODE_LEAVE_INCOGNITO" desc="The accessibility label of the switch browser mode button to leave the Incognito mode [iOS only]">
-        Leave Incognito Mode
-      </message>
       <message name="IDS_IOS_SYNC_AUTHENTICATION_ERROR_ALERT_VIEW_TITLE" desc="The title of the alert view displaying authentication errors. [Length: 20em] [iOS only]">
         Error
       </message>
       <message name="IDS_IOS_SYNC_CONFIGURE_ENCRYPTION" desc="The message displayed when the signed in user needs to enter its sync passphrase. [Length: 100em, can be multiple lines] [iOS only]">
         Passphrase required to start sync.
       </message>
       <message name="IDS_IOS_SYNC_CONFIRM_PASSPHRASE_LABEL" desc="The text for the confirm-passphrase field. [Length: 20em] [iOS only]">
         Confirm passphrase
       </message>
       <message name="IDS_IOS_SYNC_DATA_TYPES_TITLE" desc="The title for the section of the data types to sync to">
@@ skipping 227 matching lines @@
       </message>
       <message name="IDS_IOS_VOICE_SEARCH_SETTING_TITLE" desc="The title for Voice Search setting [Length: 29em] [iOS only]">
         Voice Search
       </message>
       <message name="IDS_IOS_VOICE_SEARCH_SETTING_TTS" desc="The label for setting switch enabling text-to-speech response after voice search [Length: 29em] [iOS only]">
         Speak Answers Back
       </message>
     </messages>
   </release>
 </grit>