refactor LayoutManager::save() to remove code repetition

Hey, first KDE contribution here. I was digging through code trying to fix [bug 427530](https://bugs.kde.org/show_bug.cgi?id=427530) when I found this copied-and-pasted block in LayoutManager::save(). This MR moves the block into a lambda to remove code repetition.

I am not a C++ programmer and although nothing changed that I could notice, it would be smart to sanity check and/or test this before merging.

containment/plugin/layoutmanager.cpp

@@ -514,35 +514,10 @@ void LayoutManager::save()
 
     reorderParabolicSpacers();
 
-    int startChilds{0};
-    for(int i=0; i<m_startLayout->childItems().count(); ++i) {
-        QQuickItem *item = m_startLayout->childItems()[i];
-        bool isInternalSplitter = item->property("isInternalViewSplitter").toBool();
-        bool isParabolicEdgeSpacer = item->property("isParabolicEdgeSpacer").toBool();
-        if (!isInternalSplitter && !isParabolicEdgeSpacer) {
-            QVariant appletVariant = item->property("applet");
-            if (!appletVariant.isValid()) {
-                continue;
-            }
-
-            QObject *applet = appletVariant.value<QObject *>();
-
-            if (!applet) {
-                continue;
-            }
-
-            uint id = applet->property("id").toUInt();
-
-            if (id>0) {
-                startChilds++;
-                appletIds << id;
-            }
-        }
-    }
-
-    int mainChilds{0};
-    for(int i=0; i<m_mainLayout->childItems().count(); ++i) {
-        QQuickItem *item = m_mainLayout->childItems()[i];
+    auto collectLayoutAppletIds = [](QQuickItem *layout, QList<int> &appletIds) {
+        int childCount = 0;
+        for (int i=0; i<layout->childItems().count(); ++i) {
+            QQuickItem *item = layout->childItems()[i];
             bool isInternalSplitter = item->property("isInternalViewSplitter").toBool();
             bool isParabolicEdgeSpacer = item->property("isParabolicEdgeSpacer").toBool();
             if (!isInternalSplitter && !isParabolicEdgeSpacer) {
@@ -560,37 +535,17 @@ void LayoutManager::save()
                 uint id = applet->property("id").toUInt();
 
                 if (id>0) {
-                mainChilds++;
+                    childCount++;
                     appletIds << id;
                 }
             }
         }
+        return childCount;
+    };
 
-    int endChilds{0};
-    for(int i=0; i<m_endLayout->childItems().count(); ++i) {
-        QQuickItem *item = m_endLayout->childItems()[i];
-        bool isInternalSplitter = item->property("isInternalViewSplitter").toBool();
-        bool isParabolicEdgeSpacer = item->property("isParabolicEdgeSpacer").toBool();
-        if (!isInternalSplitter && !isParabolicEdgeSpacer) {
-            QVariant appletVariant = item->property("applet");
-            if (!appletVariant.isValid()) {
-                continue;
-            }
-
-            QObject *applet = appletVariant.value<QObject *>();
-
-            if (!applet) {
-                continue;
-            }
-
-            uint id = applet->property("id").toUInt();
-
-            if (id>0) {
-                endChilds++;
-                appletIds << id;
-            }
-        }
-    }
+    int startChilds = collectLayoutAppletIds(m_startLayout, appletIds);
+    int mainChilds  = collectLayoutAppletIds(m_mainLayout,  appletIds);
+    int endChilds   = collectLayoutAppletIds(m_endLayout,   appletIds);
 
     Latte::Types::Alignment alignment = static_cast<Latte::Types::Alignment>((*m_configuration)["alignment"].toInt());