Remove obsolete chromeos specific code

chrome/browser/ui/gtk/gtk_util.h

 // Copyright (c) 2012 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_UI_GTK_GTK_UTIL_H_
 #define CHROME_BROWSER_UI_GTK_GTK_UTIL_H_
 #pragma once
 
 #include <gtk/gtk.h>
 #include <string>
@@ skipping 275 matching lines @@
 // in a view based Window.
 void ShowDialog(GtkWidget* dialog);
 void ShowDialogWithLocalizedSize(GtkWidget* dialog,
                                  int width_id,
                                  int height_id,
                                  bool resizeable);
 void ShowDialogWithMinLocalizedWidth(GtkWidget* dialog,
                                      int width_id);
 
 // Wrapper to present a window. On Linux, it just calls gtk_window_present or
-// gtk_window_present_with_time for non-zero timestamp. For ChromeOS, it first
-// finds the host window of the dialog contents and then present it.
+// gtk_window_present_with_time for non-zero timestamp.
 void PresentWindow(GtkWidget* window, int timestamp);
 
-// Get real window for given dialog. On ChromeOS, this gives the native dialog
-// host window. On Linux, it merely returns the passed in dialog.
-GtkWindow* GetDialogWindow(GtkWidget* dialog);
-
 // Gets dialog window bounds.
 gfx::Rect GetDialogBounds(GtkWidget* dialog);
 
 // Returns the stock menu item label for the "preferences" item - returns an
 // empty string if no stock item found.
 string16 GetStockPreferencesMenuLabel();
 
 // Checks whether a widget is actually visible, i.e. whether it and all its
 // ancestors up to its toplevel are visible.
 bool IsWidgetAncestryVisible(GtkWidget* widget);
@@ skipping 17 matching lines @@
 void ApplyMessageDialogQuirks(GtkWidget* dialog);
 
 // Performs Cut/Copy/Paste operation on the |window|.
 void DoCut(BrowserWindow* window);
 void DoCopy(BrowserWindow* window);
 void DoPaste(BrowserWindow* window);
 
 }  // namespace gtk_util
 
 #endif  // CHROME_BROWSER_UI_GTK_GTK_UTIL_H_