Add native button to MouseEvent

Summary:
This adds the nativeButton to the MouseEvent allowing the InputEventSpy
to use this information. Also the InputEventFilter can be adjusted to
make use of it.

Reviewers: #kwin

Subscribers: graesslin, kwin

Tags: #kwin

Differential Revision: https://phabricator.kde.org/D3875

input_event.h

@@ -61,12 +61,21 @@ public:
         m_modifiersRelevantForShortcuts = mods;
     }
 
+    quint32 nativeButton() const {
+        return m_nativeButton;
+    }
+
+    void setNativeButton(quint32 button) {
+        m_nativeButton = button;
+    }
+
 private:
     QSizeF m_delta;
     QSizeF m_deltaUnccelerated;
     quint64 m_timestampMicroseconds;
     LibInput::Device *m_device;
     Qt::KeyboardModifiers m_modifiersRelevantForShortcuts = Qt::KeyboardModifiers();
+    quint32 m_nativeButton = 0;
 };
 
 class WheelEvent : public QWheelEvent

pointer_input.cpp

@@ -259,6 +259,7 @@ void PointerInputRedirection::processButton(uint32_t button, InputRedirection::P
     MouseEvent event(type, m_pos, buttonToQtMouseButton(button), m_qtButtons,
                      m_input->keyboardModifiers(), time, QSizeF(), QSizeF(), 0, device);
     event.setModifiersRelevantForGlobalShortcuts(m_input->modifiersRelevantForGlobalShortcuts());
+    event.setNativeButton(button);
 
     m_input->processSpies(std::bind(&InputEventSpy::pointerEvent, std::placeholders::_1, &event));
     m_input->processFilters(std::bind(&InputEventFilter::pointerEvent, std::placeholders::_1, &event, button));