This CL replaces std::string user_id in ash/* with AccountId.

chrome/browser/ui/browser_finder.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/browser_finder.h"
 
 #include "chrome/browser/profiles/profile.h"
 #include "chrome/browser/ui/browser_iterator.h"
 #include "chrome/browser/ui/browser_list.h"
 #include "chrome/browser/ui/browser_window.h"
 #include "chrome/browser/ui/tab_contents/tab_contents_iterator.h"
 #include "chrome/browser/ui/tabs/tab_strip_model.h"
 #include "content/public/browser/navigation_controller.h"
 
 #if defined(OS_CHROMEOS)
 #include "chrome/browser/ui/ash/multi_user/multi_user_util.h"
 #include "chrome/browser/ui/ash/multi_user/multi_user_window_manager.h"
+#include "components/signin/core/account_id/account_id.h"
 #endif
 
 using content::WebContents;
 
 namespace {
 
 
 // Type used to indicate to match anything.
 const int kMatchAny                     = 0;
 
@@ skipping 19 matching lines @@
     return false;
   }
 
 #if defined(OS_CHROMEOS)
   // Get the profile on which the window is currently shown.
   // MultiUserWindowManager might be NULL under test scenario.
   chrome::MultiUserWindowManager* const window_manager =
       chrome::MultiUserWindowManager::GetInstance();
   Profile* shown_profile = nullptr;
   if (window_manager) {
-    const std::string& shown_user_id = window_manager->GetUserPresentingWindow(
+    const AccountId& shown_account_id = window_manager->GetUserPresentingWindow(
         browser->window()->GetNativeWindow());
-    shown_profile = shown_user_id.empty()
-                        ? nullptr
-                        : multi_user_util::GetProfileFromUserID(shown_user_id);
+    shown_profile =
+        shown_account_id.is_valid()
+            ? multi_user_util::GetProfileFromAccountId(shown_account_id)
+            : nullptr;
   }
 #endif
 
   if (match_types & kMatchOriginalProfile) {
     if (browser->profile()->GetOriginalProfile() !=
         profile->GetOriginalProfile())
       return false;
 #if defined(OS_CHROMEOS)
     if (shown_profile &&
         shown_profile->GetOriginalProfile() != profile->GetOriginalProfile()) {
@@ skipping 161 matching lines @@
 
 size_t GetBrowserCount(Profile* profile, HostDesktopType type) {
   return GetBrowserCountImpl(profile, type, kMatchAny);
 }
 
 size_t GetTabbedBrowserCount(Profile* profile, HostDesktopType type) {
   return GetBrowserCountImpl(profile, type, kMatchTabbed);
 }
 
 }  // namespace chrome