Mac: make save/open dialogs operate as tab-modal sheets....

chrome/browser/cocoa/history_menu_cocoa_controller.mm

Index: chrome/browser/cocoa/history_menu_cocoa_controller.mm
diff --git a/chrome/browser/cocoa/history_menu_cocoa_controller.mm b/chrome/browser/cocoa/history_menu_cocoa_controller.mm
index 89dd2f893e1ec297e457b824769dbff49c231f2c..17ba727c053e1c0bcf9779f8b5cefda11fc1b14a 100644
--- a/chrome/browser/cocoa/history_menu_cocoa_controller.mm
+++ b/chrome/browser/cocoa/history_menu_cocoa_controller.mm
@@ -2,7 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-#include "chrome/app/chrome_dll_resource.h"  // IDC_HISTORY_MENU
+#include "chrome/app/chrome_dll_resource.h"  // IDC_*
 #include "chrome/browser/browser.h"
 #import "chrome/browser/cocoa/history_menu_cocoa_controller.h"
 #include "chrome/browser/browser_list.h"
@@ -59,4 +59,13 @@
   [self openURLForItem:item];
 }
 
+- (BOOL)validateUserInterfaceItem:(id<NSValidatedUserInterfaceItem>)item {
+  if (Browser* browser = BrowserList::GetLastActive()) {
+    return browser->command_updater()->IsCommandEnabled(
+                                          IDC_HISTORY_MENU_CONTENTS) ? YES : NO;
+  }
+  // Enable history items when there's no browser window.
+  return YES;
+}
+
 @end  // HistoryMenuCocoaController