linux_aura: Use GTK button borders in GTK theme mode.

chrome/browser/ui/libgtk2ui/gtk2_border.h

+// Copyright 2014 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 CHROME_BROWSER_UI_LIBGTK2UI_GTK2_BORDER_H_
+#define CHROME_BROWSER_UI_LIBGTK2UI_GTK2_BORDER_H_
+
+#include "ui/gfx/image/image_skia.h"
+#include "ui/views/border.h"
+
+namespace gfx {
+class Canvas;
+}
+
+namespace views {
+class CustomButton;
+}
+
+namespace libgtk2ui {
+class Gtk2UI;
+
+// Draws a gtk button border, and manages the memory of the resulting pixbufs.
+class Gtk2Border : public views::Border {
+ public:
+  Gtk2Border(Gtk2UI* gtk2_ui,
+             views::CustomButton* owning_button,
+             views::Border* border);
+  virtual ~Gtk2Border();
+
+  // Called on theme changes. We invalidate the layout, drop our cached images,
+  // and update our GTK state.
+  void InvalidateAndSetUsesGtk(bool use_gtk);
+
+  // Overridden from views::Border:
+  virtual void Paint(const views::View& view, gfx::Canvas* canvas) OVERRIDE;
+  virtual gfx::Insets GetInsets() const OVERRIDE;
+  virtual gfx::Size GetMinimumSize() const OVERRIDE;
+
+ private:
+  Gtk2UI* gtk2_ui_;
+  bool use_gtk_;
+
+  gfx::ImageSkia hovered_;
+  gfx::ImageSkia pressed_;
+
+  // The view to which we are a border. We keep track of this so that we can
+  // force invalidate the layout on theme changes.
+  views::CustomButton* owning_button_;
+
+  // Since we don't want to expose the concept of whether we're using a GTK
+  // theme down to the cross platform views layer, we keep a normal Border and
+  // delegate to it whenever we aren't in GTK theme mode.
+  scoped_ptr<views::Border> border_;
+
+  DISALLOW_COPY_AND_ASSIGN(Gtk2Border);
+};
+
+}  // namespace libgtk2ui
+
+#endif  // CHROME_BROWSER_UI_LIBGTK2UI_GTK2_BORDER_H_