use the right NativeTheme on bubbles + dialogs on Aura Linux

chrome/browser/ui/libgtk2ui/gtk2_ui.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/libgtk2ui/gtk2_ui.h"
 
 #include <set>
 
 #include "base/command_line.h"
 #include "base/debug/leak_annotations.h"
@@ skipping 431 matching lines @@
 
   gint cursor_blink_time = kGtkDefaultCursorBlinkTime;
   gboolean cursor_blink = TRUE;
   g_object_get(gtk_settings_get_default(),
                "gtk-cursor-blink-time", &cursor_blink_time,
                "gtk-cursor-blink", &cursor_blink,
                NULL);
   return cursor_blink ? (cursor_blink_time / kGtkCursorBlinkCycleFactor) : 0.0;
 }
 
-ui::NativeTheme* Gtk2UI::GetNativeTheme() const {
+ui::NativeTheme* Gtk2UI::GetNativeTheme(aura::Window* window) const {
+  ui::NativeTheme* native_theme_override = NULL;
+  if (!native_theme_overrider_.is_null())
+    native_theme_override = native_theme_overrider_.Run(window);
+
+  if (native_theme_override)
+    return native_theme_override;
+
   return NativeThemeGtk2::instance();
 }
 
+void Gtk2UI::SetNativeThemeOverride(const NativeThemeGetter& callback) {
+  native_theme_overrider_ = callback;
+}
+
 bool Gtk2UI::GetDefaultUsesSystemTheme() const {
   scoped_ptr<base::Environment> env(base::Environment::Create());
 
   switch (base::nix::GetDesktopEnvironment(env.get())) {
     case base::nix::DESKTOP_ENVIRONMENT_GNOME:
     case base::nix::DESKTOP_ENVIRONMENT_UNITY:
     case base::nix::DESKTOP_ENVIRONMENT_XFCE:
       return true;
     case base::nix::DESKTOP_ENVIRONMENT_KDE3:
     case base::nix::DESKTOP_ENVIRONMENT_KDE4:
@@ skipping 914 matching lines @@
 
   FOR_EACH_OBSERVER(views::NativeThemeChangeObserver, theme_change_observers_,
                     OnNativeThemeChanged());
 }
 
 }  // namespace libgtk2ui
 
 views::LinuxUI* BuildGtk2UI() {
   return new libgtk2ui::Gtk2UI;
 }