support close button for activity switcher

src/shell/qmlpackages/desktop/contents/activitymanager/ActivityManager.qml

@@ -18,7 +18,19 @@
  */
 
 import QtQuick 2.0
+import org.kde.plasma.components 2.0 as PlasmaComponents
 
 Rectangle {
+    id: root
     color: "red"
+    signal closed()
+
+    PlasmaComponents.ToolButton {
+        anchors {
+            top: parent.top
+            right: parent.right
+        }
+        iconSource: "window-close"
+        onClicked: root.closed()
+    }
 }

src/shell/qmlpackages/desktop/contents/views/Desktop.qml

@@ -53,7 +53,8 @@ Rectangle {
         if (sidePanelStack.state == "activityManager") {
             sidePanelStack.state = "closed";
         } else {
-            sidePanelStack.push(Qt.resolvedUrl("../activitymanager/ActivityManager.qml"));
+            var page = sidePanelStack.push(Qt.resolvedUrl("../activitymanager/ActivityManager.qml"));
+            page.closed.connect(function(){sidePanelStack.state = "closed";});
             sidePanelStack.state = "activityManager";
         }
     }