Aura/GTK integration: Create a small stub library that can talk to GTK.

ui/base/linux_ui.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 UI_BASE_LINUX_SHELL_LINUX_SHELL_H_
+#define UI_BASE_LINUX_SHELL_LINUX_SHELL_H_
+#pragma once
+
+#include "ui/base/ui_export.h"
+#include "third_party/skia/include/core/SkColor.h"
+
+// The main entrypoint into Linux toolkit specific code. GTK code should only
+// be executed behind this interface.
+
+namespace gfx {
+class Image;
+}
+
+namespace ui {
+
+// Adapter class with targets to render like different toolkits. Set by any
+// project that wants to do linux desktop native rendering.
+//
+// TODO(erg): We're hardcoding GTK2, when we'll need to have backends for (at
+// minimum) GTK2 and GTK3. LinuxShell::instance() should actually be a very
+// complex method that pokes around with dlopen against a libuigtk2.so, a
+// liuigtk3.so, etc.
+class UI_EXPORT LinuxUI {
+ public:
+  // Sets the dynamically loaded singleton that draws the desktop native UI.
+  static void SetInstance(LinuxUI* instance);
+
+  // Returns a LinuxShell instance for the toolkit used in the user's desktop
+  // environment.
+  //
+  // Can return NULL, in case no toolkit has been set. (For example, if we're
+  // running with the "--ash" flag.)
+  static const LinuxUI* instance();
+
+  // Returns an themed image per theme_provider.h
+  virtual bool UseNativeTheme() const = 0;
+  virtual gfx::Image* GetThemeImageNamed(int id) const = 0;
+  virtual SkColor GetColor(int id) const = 0;
+
+  virtual ~LinuxUI() {}

[sky, 2012/06/06 21:04:07]

nit: destructors before all other methods (including statics).

+};
+
+}  // namespace ui
+
+#endif  // UI_BASE_LINUX_SHELL_LINUX_SHELL_H_