crOS: Display a reauth dialog for Mirror reauthentication

On Chrome OS, with Mirror account reconciliation enabled, it is possible
that an account's session expires server-side without Chrome detecting
it. In these cases, Gaia sends us a re-authentication header message
with the account's email that needs re-authentication.

Currently, Chrome OS displays the Account Manager Settings page for
these messages. Fix it to show a re-authentication dialog.

Bug: b/136640443
Change-Id: I9a88a3115908a663ac0b9f895656782ff0fb8923
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1695351Reviewed-by: Boris Sazonov <bsazonov@chromium.org>
Commit-Queue: Kush Sinha <sinhak@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676093}

chrome/browser/signin/chrome_signin_helper.cc

@@ -59,6 +59,7 @@
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/ui/settings_window_manager_chromeos.h"
+#include "chrome/browser/ui/webui/signin/inline_login_handler_dialog_chromeos.h"
 #include "chromeos/constants/chromeos_switches.h"
 #endif
 
@@ -210,14 +211,26 @@ void ProcessMirrorHeaderUIThread(
     //
     // - Going Incognito (already handled in above switch-case).
     // - Displaying the Account Manager for managing accounts.
+    // - Displaying a reauthentication window: Enterprise GSuite Accounts could
+    // have been forced through an online in-browser sign-in for sensitive
+    // webpages, thereby decreasing their session validity. After their session
+    // expires, they will receive a "Mirror" re-authentication request for all
+    // Google web properties.
 
     // Do not display Account Manager if the navigation happened in the
     // "background".
     if (!chrome::FindBrowserWithWebContents(web_contents))
       return;
 
-    chrome::SettingsWindowManager::GetInstance()->ShowOSSettings(
-        profile, chrome::kAccountManagerSubPage);
+    if (manage_accounts_params.email.empty()) {
+      // Display Account Manager for managing accounts.
+      chrome::SettingsWindowManager::GetInstance()->ShowOSSettings(
+          profile, chrome::kAccountManagerSubPage);
+    } else {
+      // Display a re-authentication dialog.
+      chromeos::InlineLoginHandlerDialogChromeOS::Show(
+          manage_accounts_params.email);
+    }
     return;
   }