Turn on session restore by default for mac on Lion

chrome/browser/ui/cocoa/window_restore_utils.mm

+// Copyright (c) 2011 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 "chrome/browser/ui/cocoa/window_restore_utils.h"
+
+#import <Foundation/Foundation.h>
+
+#include "base/mac/mac_util.h"
+
+namespace restore_utils {
+
+bool IsWindowRestoreEnabled() {
+  if (!base::mac::IsOSLionOrLater())
+    return false;
+
+  NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
+  // The defaults must be synchronized here otherwise a stale value will be
+  // returned for an indeterminate amount of time.
+  [defaults synchronize];
+  return !![defaults boolForKey:@"NSQuitAlwaysKeepsWindows"];
+}
+
+}  // namespace restore_utils