Mac: reform our shutdown routine.

chrome/browser/browser_list_mac.mm

Index: chrome/browser/browser_list_mac.mm
diff --git a/chrome/browser/browser_list_mac.mm b/chrome/browser/browser_list_mac.mm
new file mode 100644
index 0000000000000000000000000000000000000000..f65a3e5c5f26123d12ef3b7f3b58c798e2d711bc
--- /dev/null
+++ b/chrome/browser/browser_list_mac.mm
@@ -0,0 +1,15 @@
+// Copyright (c) 2010 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/browser_list.h"
+
+#include "chrome/browser/browser_shutdown.h"
+#import "chrome/browser/chrome_browser_application_mac.h"
+
+// static
+void BrowserList::AllBrowsersClosed() {
+  // Only terminate after all browsers are closed if trying quit.
+  if (browser_shutdown::IsTryingToQuit())
+    chrome_browser_application_mac::Terminate();
+}