Add always-on-top property to app windows

chrome/browser/ui/gtk/browser_window_gtk.cc

 // Copyright 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.
 
 #include "chrome/browser/ui/gtk/browser_window_gtk.h"
 
 #include <gdk/gdkkeysyms.h>
 
 #include <algorithm>
 #include <string>
@@ skipping 701 matching lines @@
 
 void BrowserWindowGtk::FlashFrame(bool flash) {
   // May not be respected by all window managers.
   gtk_window_set_urgency_hint(window_, flash);
 }
 
 bool BrowserWindowGtk::IsAlwaysOnTop() const {
   return false;
 }
 
+void BrowserWindowGtk::SetAlwaysOnTop(bool always_on_top) {
+  // Not implemented for browser windows.
+  NOTIMPLEMENTED();
+}
+
 gfx::NativeWindow BrowserWindowGtk::GetNativeWindow() {
   return window_;
 }
 
 BrowserWindowTesting* BrowserWindowGtk::GetBrowserWindowTesting() {
   NOTIMPLEMENTED();
   return NULL;
 }
 
 StatusBubble* BrowserWindowGtk::GetStatusBubble() {
@@ skipping 1681 matching lines @@
           wm_type == ui::WM_OPENBOX ||
           wm_type == ui::WM_XFWM4);
 }
 
 // static
 BrowserWindow* BrowserWindow::CreateBrowserWindow(Browser* browser) {
   BrowserWindowGtk* browser_window_gtk = new BrowserWindowGtk(browser);
   browser_window_gtk->Init();
   return browser_window_gtk;
 }