Switch to doing user-resizing via system for panels on Mac

chrome/browser/ui/gtk/panels/panel_gtk.cc

 // 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.
 
 #include "chrome/browser/ui/gtk/panels/panel_gtk.h"
 
 #include <gdk/gdk.h>
 #include <gdk/gdkkeysyms.h>
 #include <X11/XF86keysym.h>
 
@@ skipping 1050 matching lines @@
   // from the panel UI.
   gtk_window_set_skip_taskbar_hint(window_, on_top);
 
   // Show always-on-top windows on all the virtual desktops.
   if (on_top)
     gtk_window_stick(window_);
   else
     gtk_window_unstick(window_);
 }
 
-void PanelGtk::EnableResizeByMouse(bool enable) {
-}
-
 void PanelGtk::UpdatePanelMinimizeRestoreButtonVisibility() {
   titlebar_->UpdateMinimizeRestoreButtonVisibility();
 }
 
 gfx::Size PanelGtk::GetNonClientFrameSize() const {
   GtkAllocation window_allocation;
   gtk_widget_get_allocation(window_container_, &window_allocation);
   GtkAllocation contents_allocation;
   gtk_widget_get_allocation(contents_expanded_, &contents_allocation);
   return gfx::Size(window_allocation.width - contents_allocation.width,
@@ skipping 149 matching lines @@
 }
 
 panel::CornerStyle GtkNativePanelTesting::GetWindowCornerStyle() const {
   return panel_gtk_->corner_style_;
 }
 
 bool GtkNativePanelTesting::EnsureApplicationRunOnForeground() {
   // Not needed on GTK.
   return true;
 }