Lock profile before sign in when force sign in is enabled.

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. If you update this file, be sure also to update
 chromium_strings.grd. -->
 
 <grit base_dir="." latest_public_release="0" current_release="1"
       output_all_resource_defines="false" source_lang_id="en" enc_check="möl">
   <outputs>
     <output filename="grit/google_chrome_strings.h" type="rc_header">
@@ skipping 763 matching lines @@
           You're now signed in to Chrome! Sync is disabled by your administrator.
         </message>
         <message name="IDS_SYNC_WRONG_EMAIL" desc="Message shown when sync setup failed due to the user entering the wrong email address for sign-in.">
           You were signed in to Chrome as <ph name="USER_EMAIL_ADDRESS">$1<ex>foo@gmail.com</ex></ph>. Please use the same account to sign in again.
         </message>
         <message name="IDS_ONE_CLICK_SIGNIN_CONFIRM_EMAIL_DIALOG_MESSAGE" desc="Error message to display when setting up sync for a second time and the user name is different from the previous user name.">
           Someone previously signed in to Chrome on this computer as <ph name="ACCOUNT_EMAIL_LAST">$1<ex>user@example.com</ex></ph>. If that isn't your account, create a new Chrome user to keep your information separate.
 
 Signing in anyway will merge Chrome information like bookmarks, history, and other settings to <ph name="ACCOUNT_EMAIL_NEW">$2<ex>user@example.com</ex></ph>.
         </message>
+        <message name="IDS_SYNC_USED_PROFILE_ERROR" desc="An error message shown when user tries to sign in to a profile that is used by other user name before.">
+          Someone previously signed in to Chrome on this computer as <ph name="ACCOUNT_EMAIL_LAST">$1<ex>user@example.com</ex></ph>. Please create a new Chrome user to keep your information separate.
+        </message>
       </if>
 
       <!-- Enterprise sign-in profile linking -->
       <if expr="not is_android">
         <message name="IDS_ENTERPRISE_SIGNIN_PROFILE_LINK_DIALOG_TITLE" desc="The title of the dialog to confirm linking the browser profile with the signed-in enterprise account">
           Important information regarding your Chrome data
         </message>
         <message name="IDS_ENTERPRISE_SIGNIN_PROFILE_LINK_MESSAGE" desc="The warning message displayed to an enterprise user about to link their profile to their Google account. This message is followed by a 'Learn more' link.">
           You are signing in with a managed account and giving its administrator control over your Google Chrome profile. Your Chrome data, such as your apps, bookmarks, history, passwords, and other settings will become permanently tied to <ph name="USER_NAME">$1<ex>pat@example.com</ex></ph>. You will be able to delete this data via the Google Accounts Dashboard, but you will not be able to associate this data with another account.
         </message>
@@ skipping 507 matching lines @@
       <message name="IDS_PRIVATE_USER_DATA_INPUT_FUTURE_DESCRIPTION" desc="Description of a security problem where the site collects private user data on an insecure page, which will result in an omnibox warning in future versions of Chrome." translateable="false">
         This page includes a password or credit card input over HTTP. A warning will appear in the URL bar starting in Chrome 56 (Jan 2017).
       </message>
       <message name="IDS_PRIVATE_USER_DATA_INPUT_DESCRIPTION" desc="Description of a security problem where the site collects private user data on an insecure page, which results in an omnibox warning." translateable="false">
         This page includes a password or credit card input over HTTP. A warning has been added the URL bar.
       </message>
 
     </messages>
   </release>
 </grit>