TabViewStyle: expose styleData.availableWidth

Change-Id: Ib209ec7311c64f172718c8baa7d7f63f6f79a3a8
Reviewed-by: Jens Bache-Wiig <jens.bache-wiig@digia.com>

src/private/TabBar.qml

@@ -192,7 +192,6 @@ FocusScope {
 
                 property Item control: tabView
                 property int index: tabindex
-                property real availableWidth: tabbar.availableWidth
 
                 property QtObject styleData: QtObject {
                     readonly property alias index: tabitem.tabindex
@@ -202,6 +201,7 @@ FocusScope {
                     readonly property alias previsousSelected: tabitem.previousSelected
                     readonly property alias hovered: tabitem.containsMouse
                     readonly property bool activeFocus: tabbar.activeFocus
+                    readonly property real availableWidth: tabbar.availableWidth
                 }
 
                 sourceComponent: loader.item ? loader.item.tab : null

src/styles/Base/TabViewStyle.qml

@@ -136,7 +136,7 @@ Style {
         scale: control.tabPosition === Qt.TopEdge ? 1 : -1
 
         property int totalOverlap: tabOverlap * (control.count - 1)
-        property real maxTabWidth: (availableWidth + totalOverlap) / control.count
+        property real maxTabWidth: (styleData.availableWidth + totalOverlap) / control.count
 
         implicitWidth: Math.round(Math.min(maxTabWidth, textitem.implicitWidth + 20))
         implicitHeight: Math.round(textitem.implicitHeight + 10)