Re-Reland Linux Window Control Alignment

ui/views/window/window_button_order_provider.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 UI_VIEWS_WINDOW_WINDOW_BUTTON_ORDER_PROVIDER_H_
+#define UI_VIEWS_WINDOW_WINDOW_BUTTON_ORDER_PROVIDER_H_
+
+#include <vector>
+
+#include "base/macros.h"
+#include "ui/views/views_export.h"
+#include "ui/views/window/frame_buttons.h"
+
+namespace views {
+
+// Stores the ordering of window control buttons. Provides a default ordering
+// of |FRAME_BUTTON_MINIMZE|, |FRAME_BUTTON_MAXIMIZE|, |FRAME_BUTTON_CLOSE|,
+// where all controls are on the trailing end of a window.
+//
+// On Linux users can provide configuration files to control the ordering. This
+// configuration is checked and overrides the defaults.
+class VIEWS_EXPORT WindowButtonOrderProvider {
+ public:
+  static WindowButtonOrderProvider* GetInstance();
+
+  const std::vector<views::FrameButton>& leading_buttons() const {
+    return leading_buttons_;
+  }
+
+  const std::vector<views::FrameButton>& trailing_buttons() const {
+    return trailing_buttons_;
+  }
+
+  void SetWindowButtonOrder(
+      const std::vector<views::FrameButton>& leading_buttons,
+      const std::vector<views::FrameButton>& trailing_buttons);
+
+ protected:
+  WindowButtonOrderProvider();
+  virtual ~WindowButtonOrderProvider();
+
+ private:
+  static WindowButtonOrderProvider* instance_;
+
+  // Layout arrangement of the window caption buttons. On linux these will be
+  // set via a WindowButtonOrderObserver. On other platforms a default
+  // arrangement of a trailing minimize, maximize, close, will be set.
+  std::vector<views::FrameButton> leading_buttons_;
+  std::vector<views::FrameButton> trailing_buttons_;
+
+  DISALLOW_COPY_AND_ASSIGN(WindowButtonOrderProvider);
+};
+
+}  // namespace views
+
+#endif  // UI_VIEWS_WINDOW_WINDOW_BUTTON_ORDER_PROVIDER_H_