Moving It2Me confirmation prompt into the Validation callback flow

remoting/resources/remoting_strings.grd

 <?xml version="1.0" encoding="UTF-8"?>
 
 <grit base_dir="." latest_public_release="0" current_release="1"
       output_all_resource_defines="false" enc_check="möl" source_lang_id="en">
   <outputs>
     <output filename="remoting/base/string_resources.h" type="rc_header">
       <emit emit_type="prepend"/>
     </output>
 
     <output filename="remoting/resources/am.pak" lang="am" type="data_package"/>
@@ skipping 1145 matching lines @@
       </message>
       <message desc="Label for button to accept remote assistance.  This button appears in the Hangouts confirm dialog." name="IDS_HANGOUTS_CONFIRM_DIALOG_ACCEPT" >
         Accept
       </message>
       <message desc="Label for button to decline remote assistance.  This button appears in the Hangouts confirm dialog." name="IDS_HANGOUTS_CONFIRM_DIALOG_DECLINE" >
         Decline
       </message>
       <message desc="Message displayed before sharing computer in 'It2Me' mode." name="IDS_SHARE_CONFIRM_DIALOG_MESSAGE" >
         Would you like to share this computer for another user to see and control?
       </message>
+      <message desc="Message displayed before sharing computer in 'It2Me' mode when the email of the remote user attempting to connect is known." name="IDS_SHARE_CONFIRM_DIALOG_MESSAGE_WITH_USERNAME" >
+        Would you like to share this computer with <ph name="CLIENT_USERNAME">{0}<ex>client@email.com</ex></ph> and allow them to see and control it?
+      </message>
       <message desc="Label for the button to accept sharing the computer in 'It2Me' mode." name="IDS_SHARE_CONFIRM_DIALOG_CONFIRM" >
         Share
       </message>
       <message desc="Label for the button to decline sharing the computer in 'It2Me' mode." name="IDS_SHARE_CONFIRM_DIALOG_DECLINE" >
         Cancel
       </message>
       <message desc="Text shown in tooltip to inform the user that a setting is managed by domain policy." name="IDS_SETTING_MANAGED_BY_POLICY">
         This setting is managed by your domain policy.
       </message>
       <message desc="Platform-specific text indicating that a component is for the Windows OS." name="IDS_FOR_PLATFORM_WINDOWS">
         For Windows 7 and above
       </message>
       <message desc="Platform-specific text indicating that a component is for the Mac OS." name="IDS_FOR_PLATFORM_MAC">
         For Mac (OS X Mavericks 10.9 and above)
       </message>
       <message desc="Text for the button the user clicks to indicate that they agree to the terms of service and want to proceed with downloading the installer." name="IDS_ACCEPT_AND_INSTALL">
         Accept and Install
       </message>
 
     </messages>
   </release>
 </grit>