chromeos: Make enterprise help dialog work in mash, part 1

chrome/browser/chromeos/login/ui/login_web_dialog.h

 // Copyright 2014 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_LOGIN_UI_LOGIN_WEB_DIALOG_H_
 #define CHROME_BROWSER_CHROMEOS_LOGIN_UI_LOGIN_WEB_DIALOG_H_
 
 #include <string>
 #include <vector>
 
@@ skipping 16 matching lines @@
   // Delegate class to get notifications from the dialog.
   class Delegate {
    public:
     // Called when dialog has been closed.
     virtual void OnDialogClosed();
 
    protected:
     virtual ~Delegate() {}
   };
 
+  // If |parent_window| is null then the dialog is placed in the modal dialog
+  // container on the primary display.
   LoginWebDialog(content::BrowserContext* browser_context,
                  Delegate* delegate,
                  gfx::NativeWindow parent_window,
                  const base::string16& title,
                  const GURL& url);
   ~LoginWebDialog() override;
 
   void Show();
 
   // Overrides default width/height for dialog.
@@ skipping 40 matching lines @@
   // Dialog display size.
   int width_;
   int height_;
 
   DISALLOW_COPY_AND_ASSIGN(LoginWebDialog);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_LOGIN_UI_LOGIN_WEB_DIALOG_H_