Qt: Implement button mapping dialogs

Source/Core/DolphinQt2/Config/Mapping/MappingButton.h

@@ -0,0 +1,36 @@
+// Copyright 2017 Dolphin Emulator Project
+// Licensed under GPLv2+
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <QPoint>
+#include <QPushButton>
+#include <QString>
+
+class ControlReference;
+class MappingWidget;
+class QEvent;
+class QMouseEvent;
+
+class MappingButton : public QPushButton
+{
+public:
+  MappingButton(MappingWidget* widget, ControlReference* ref);
+
+  void Clear();
+  void Update();
+
+private:
+  bool event(QEvent* event) override;
+  void mouseReleaseEvent(QMouseEvent* event) override;
+
+  void OnButtonPressed();
+  void OnButtonTimeout();
+  void Connect();
+  void SetBlockInputs(const bool block);
+
+  MappingWidget* m_parent;
+  ControlReference* m_reference;
+  bool m_block = false;
+};