Core: Refactor handling of "window state" actions out of MainWindow

Currently the actions for fullscreen, minimize and zoom only apply to
the main window, even if a different window is active.
Refactor the handling of these actions into a WindowSupport class, and
use that instead for the main window. In a second step, this will be
used to add the functionality to the corresponding external windows
(e.g. help and editor windows)

Change-Id: Ief2c880f40948c3bb724196d6e0cfe888b8ece89
Reviewed-by: Daniel Teske <daniel.teske@digia.com>

src/plugins/coreplugin/windowsupport.h

@@ -0,0 +1,70 @@
+/****************************************************************************
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+** This file is part of Qt Creator.
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+****************************************************************************/
+
+#ifndef WINDOWSUPPORT_H
+#define WINDOWSUPPORT_H
+
+#include "icontext.h"
+
+#include <QObject>
+
+QT_BEGIN_NAMESPACE
+class QAction;
+class QWidget;
+QT_END_NAMESPACE
+
+namespace Core {
+namespace Internal {
+
+class WindowSupport : public QObject
+{
+    Q_OBJECT
+public:
+    WindowSupport(QWidget *window, const Context &context);
+    ~WindowSupport();
+
+protected:
+    bool eventFilter(QObject *obj, QEvent *event);
+
+private slots:
+    void toggleFullScreen();
+    void updateFullScreenAction();
+
+private:
+    QWidget *m_window;
+    IContext *m_contextObject;
+    QAction *m_minimizeAction;
+    QAction *m_zoomAction;
+    QAction *m_toggleFullScreenAction;
+};
+
+} // Internal
+} // Core
+
+#endif // WINDOWSUPPORT_H