ScxmlEditor: Add missing includes

Amends 1e410e2c4d

Change-Id: I5ed585d3025d494a1062d9c7e69836b70454f78f
Reviewed-by: Jarek Kobus <jaroslaw.kobus@qt.io>

src/plugins/scxmleditor/plugin_interface/cornergrabberitem.cpp

@@ -7,6 +7,7 @@
 #include <QGraphicsScene>
 #include <QGraphicsSceneMouseEvent>
 #include <QPainter>
+#include <QPalette>
 
 using namespace ScxmlEditor::PluginInterface;
 

src/plugins/scxmleditor/plugin_interface/finalstateitem.cpp

@@ -5,6 +5,7 @@
 
 #include <QGraphicsScene>
 #include <QPainter>
+#include <QPalette>
 
 using namespace ScxmlEditor::PluginInterface;
 

src/plugins/scxmleditor/plugin_interface/historyitem.cpp

@@ -5,6 +5,7 @@
 
 #include <QGraphicsScene>
 #include <QPainter>
+#include <QPalette>
 
 using namespace ScxmlEditor::PluginInterface;
 

src/plugins/scxmleditor/plugin_interface/initialstateitem.cpp

@@ -11,6 +11,7 @@
 #include <QDataStream>
 #include <QGraphicsScene>
 #include <QPainter>
+#include <QPalette>
 
 using namespace ScxmlEditor::PluginInterface;
 

src/plugins/scxmleditor/plugin_interface/quicktransitionitem.cpp

@@ -7,6 +7,7 @@
 #include <QGraphicsScene>
 #include <QGraphicsSceneMouseEvent>
 #include <QPainter>
+#include <QPalette>
 
 using namespace ScxmlEditor::PluginInterface;