Sort out build dependencies for LinuxUI.

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_UI_H_
-#define UI_BASE_LINUX_UI_H_
-
-#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 {
-class SelectFilePolicy;
-
-// 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. LinuxUI::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:
-  virtual ~LinuxUI() {}
-
-  // Sets the dynamically loaded singleton that draws the desktop native UI.
-  static void SetInstance(LinuxUI* instance);
-
-  // Returns a LinuxUI 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 bool GetColor(int id, SkColor* color) const = 0;
-};
-
-}  // namespace ui
-
-#endif  // UI_BASE_LINUX_UI_H_