[iOS] Add Strings for sign-in notification infobar.

This patch introduces two strings which are being considered as the
title for a new infobar notification that will display the existing
user signed-in account when cookies are re-generated.

Screenshots:
https://drive.google.com/open?id=1qzxdFZg_gOQW8hUJg7MMQzJU8pmjUP42
https://drive.google.com/open?id=1dHopX_WVr45XMsdVaQ2HGtD9-5cgMXAc

Bug: 1145592
Change-Id: I4c94522d50e278cfd151fc750f2888d17b0ee95d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2517456
Commit-Queue: Nohemi Fernandez <fernandex@chromium.org>
Reviewed-by: Jérôme Lebel <jlebel@chromium.org>
Cr-Commit-Position: refs/heads/master@{#824521}

ios/chrome/app/strings/ios_strings.grd

@@ -2100,6 +2100,12 @@ Try to use a unique password for every site.
       <message name="IDS_IOS_SIGN_TRUSTED_VAULT_ERROR_DIALOG_MESSAGE" desc="Alert message to display an error after a reauthentication, related to IDS_IOS_SIGN_TRUSTED_VAULT_ERROR_DIALOG_TITLE [iOS only]">
         Error code: <ph name="ERROR_CODE">$1<ex>2</ex></ph>
       </message>
+      <message name="IDS_IOS_SIGNIN_ACCOUNT_NOTIFICATION_TITLE" desc="Notification title for the user's signed-in state [iOS only]">
+      Signed in to Chrome
+      </message>
+      <message name="IDS_IOS_SIGNIN_ACCOUNT_NOTIFICATION_TITLE_WITH_USERNAME" desc="Notification title for the user's signed-in state that includes the user's full name [iOS only]">
+      Signed in as <ph name="USER">$1<ex>Jane Doe</ex></ph>
+      </message>
       <message name="IDS_IOS_SPOTLIGHT_KEYWORD_EIGHT" desc="Keyword used in Spotlight that will be linked to the Chrome App. [iOS only]">
         Online
       </message>

ios/chrome/app/strings/ios_strings_grd/IDS_IOS_SIGNIN_ACCOUNT_NOTIFICATION_TITLE.png.sha1

+a0d7ebddb294f1ef5567af226a8a5b057c389677
\ No newline at end of file

ios/chrome/app/strings/ios_strings_grd/IDS_IOS_SIGNIN_ACCOUNT_NOTIFICATION_TITLE_WITH_USERNAME.png.sha1

+2f6d0ca96ce7f0335cd1b2d1902bc8c22ba5d583
\ No newline at end of file