Improve some naming

ui/views/linux_ui/system_theme_change_observer.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_LINUX_UI_SYSTEM_THEME_CHANGE_OBSERVER_H_
+#define UI_VIEWS_LINUX_UI_SYSTEM_THEME_CHANGE_OBSERVER_H_
+
+#include "ui/views/views_export.h"
+
+namespace views {
+
+// Observers which are notified when the system theme changes.
+class VIEWS_EXPORT SystemThemeChangeObserver {
+ public:
+  virtual ~SystemThemeChangeObserver() {}
+
+  // Called whenever the underlying platform changes its theme.
+  virtual void OnSystemThemeChanged() = 0;
+};
+
+}  // namespace views
+
+#endif  // UI_VIEWS_LINUX_UI_SYSTEM_THEME_CHANGE_OBSERVER_H_