Added the "Show as Tab" option for popups on OSX

chrome/browser/ui/cocoa/browser_window_command_handler.mm

Index: chrome/browser/ui/cocoa/browser_window_command_handler.mm
diff --git a/chrome/browser/ui/cocoa/browser_window_command_handler.mm b/chrome/browser/ui/cocoa/browser_window_command_handler.mm
index 4f88b46e4ff48c3a000a95af8e37fbb3a2a80d5f..192fd49f9812d7171ed49f97656d375a6c98b731 100644
--- a/chrome/browser/ui/cocoa/browser_window_command_handler.mm
+++ b/chrome/browser/ui/cocoa/browser_window_command_handler.mm
@@ -219,6 +219,13 @@ Browser* FindBrowserForSender(id sender, NSWindow* window) {
         [menuItem setHidden:YES];
         enable = NO;
       }
+      break;
+    }
+    case IDC_SHOW_AS_TAB: {
+      // Hide this menu option if the window is tabbed.
+      NSMenuItem* menuItem = base::mac::ObjCCast<NSMenuItem>(item);
+      [menuItem setHidden:browser->is_type_tabbed()];
+      break;
     }
     default:
       // Special handling for the contents of the Text Encoding submenu. On