Extract duplicated code in browser_tests for closing a browser.

chrome/browser/app_controller_mac_browsertest.mm

 // 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.
 
 #import <Carbon/Carbon.h>
 #import <Cocoa/Cocoa.h>
 #import <Foundation/Foundation.h>
 #import <Foundation/NSAppleEventDescriptor.h>
 #import <objc/message.h>
 #import <objc/runtime.h>
@@ skipping 646 matching lines @@
   ui_test_utils::NavigateToURLWithDisposition(
       browser(), GURL(test_url3), NEW_WINDOW,
       ui_test_utils::BROWSER_TEST_WAIT_FOR_BROWSER);
   EXPECT_EQ(g_handoff_url, test_url3);
 
   // Check that there are exactly 2 browsers.
   BrowserList* active_browser_list =
       BrowserList::GetInstance(chrome::GetActiveDesktop());
   EXPECT_EQ(2u, active_browser_list->size());
 
-  // Close the one and only tab for the second browser window.
+  // Close the second browser window (which only has 1 tab left).
   Browser* browser2 = active_browser_list->get(1);
-  CloseTab(browser2, 0);
-  base::RunLoop().RunUntilIdle();
+  CloseBrowserSynchronously(browser2);
   EXPECT_EQ(g_handoff_url, test_url2);
 
   // The URLs of incognito windows should not be passed to Handoff.
   GURL test_url4 = embedded_test_server()->GetURL("/simple.html");
   ui_test_utils::NavigateToURLWithDisposition(
       browser(), GURL(test_url4), OFF_THE_RECORD,
       ui_test_utils::BROWSER_TEST_WAIT_FOR_BROWSER);
   EXPECT_EQ(g_handoff_url, GURL());
 
   // Open a new tab in the incognito window.
   EXPECT_EQ(2u, active_browser_list->size());
   Browser* browser3 = active_browser_list->get(1);
   ui_test_utils::NavigateToURLWithDisposition(
       browser3, test_url4, NEW_FOREGROUND_TAB,
       ui_test_utils::BROWSER_TEST_WAIT_FOR_TAB);
   EXPECT_EQ(g_handoff_url, GURL());
 
   // Navigate the current tab in the incognito window.
   ui_test_utils::NavigateToURL(browser3, test_url1);
   EXPECT_EQ(g_handoff_url, GURL());
 
   // Activate the original browser window.
   Browser* browser1 = active_browser_list->get(0);
   browser1->window()->Show();
   EXPECT_EQ(g_handoff_url, test_url2);
 }
 
 }  // namespace