Welcome page: display the scroll decorator

To give a hint the news list is scrollable

ground/openpilotgcs/src/plugins/welcome/qml/NewsPanel.qml

@@ -28,6 +28,10 @@ Item {
         clip: true
     }
 
+    ScrollDecorator {
+        flickableItem: view
+    }
+
     XmlListModel {
         id: xmlModel
         source: "http://www.openpilot.org/feed/"

ground/openpilotgcs/src/plugins/welcome/qml/ScrollDecorator.qml

@@ -0,0 +1,37 @@
+import QtQuick 1.1
+
+Rectangle {
+    id: scrollDecorator
+
+    property Flickable flickableItem: null
+
+    Loader {
+        sourceComponent: scrollDecorator.flickableItem ? scrollBar : undefined
+    }
+
+    Component {
+        id: scrollBar
+        Rectangle {
+            property Flickable flickable: scrollDecorator.flickableItem
+
+            parent: flickable
+            anchors.right: parent.right
+
+            smooth: true
+            radius: 2
+            color: "gray"
+            border.color: "lightgray"
+            border.width: 1.0
+            opacity: flickable.moving ? 0.8 : 0.4
+
+            Behavior on opacity {
+                NumberAnimation { duration: 500 }
+            }
+
+            width: 4
+            height: flickable.height * (flickable.height / flickable.contentHeight)
+            y: flickable.height * (flickable.contentY / flickable.contentHeight)
+            visible: flickable.height < flickable.contentHeight
+        }
+    }
+}

ground/openpilotgcs/src/plugins/welcome/welcome.qrc

@@ -5,6 +5,7 @@
         <file>qml/SitesPanel.qml</file>
         <file>qml/WelcomePageButton.qml</file>
         <file>qml/NewsPanel.qml</file>
+        <file>qml/ScrollDecorator.qml</file>
         <file>qml/images/welcome-news-bg.png</file>
         <file>qml/images/welcome-op-logo.png</file>
         <file>qml/images/button-label.png</file>