Fix compile error

Change-Id: Icf20d3f83a0792e59e9bd3a305d883d32ab66c77
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>

src/plugins/qmldesigner/components/itemlibrary/itemlibrarymodel.cpp

@@ -29,8 +29,6 @@
 #include "itemlibraryitem.h"
 #include "itemlibrarysection.h"
 
-#include <components/previewtooltip/previewtooltipbackend.h>
-
 #include <model.h>
 #include <nodehints.h>
 #include <nodemetainfo.h>

src/plugins/qmldesigner/components/itemlibrary/itemlibraryresourceview.cpp

@@ -29,7 +29,6 @@
 
 #include <theme.h>
 #include <imagecache.h>
-#include <previewtooltip/previewtooltipbackend.h>
 
 #include <QAction>
 #include <QActionGroup>

src/plugins/qmldesigner/components/itemlibrary/itemlibraryresourceview.h

@@ -25,6 +25,8 @@
 
 #pragma once
 
+#include <previewtooltip/previewtooltipbackend.h>
+
 #include <QListView>
 
 QT_BEGIN_NAMESPACE
@@ -33,7 +35,6 @@ QT_END_NAMESPACE
 
 namespace QmlDesigner {
 
-class PreviewTooltipBackend;
 class ImageCache;
 
 class ItemLibraryResourceView : public QListView {

src/plugins/qmldesigner/components/itemlibrary/itemlibrarywidget.cpp

@@ -38,7 +38,6 @@
 #include <itemlibrarymodel.h>
 #include <metainfo.h>
 #include <model.h>
-#include <previewtooltip/previewtooltipbackend.h>
 #include <rewritingexception.h>
 #include <qmldesignerconstants.h>
 #include <qmldesignerplugin.h>

src/plugins/qmldesigner/components/itemlibrary/itemlibrarywidget.h

@@ -30,6 +30,7 @@
 
 #include <utils/fancylineedit.h>
 #include <utils/dropsupport.h>
+#include <previewtooltip/previewtooltipbackend.h>
 
 #include <QFrame>
 #include <QToolButton>
@@ -55,7 +56,6 @@ class CustomFileSystemModel;
 
 class ItemLibraryModel;
 class ItemLibraryResourceView;
-class PreviewTooltipBackend;
 class ImageCache;
 class ImageCacheCollector;