WelcomePage: Fix minimum size

The Welcome page should not impose a minimum size on Qt Creator.
We use a ScrollArea instead. This was a regression introduced by porting
to Qt Quick 2.

Task-number: QTCREATORBUG-10505
Change-Id: I5bbe4a18bdb96e91723987995a3632487bab536d
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>
Reviewed-by: Eike Ziller <eike.ziller@digia.com>

src/plugins/welcome/welcomeplugin.cpp

@@ -165,16 +165,15 @@ WelcomeMode::WelcomeMode() :
     styledBar->setObjectName(QLatin1String("WelcomePageStyledBar"));
     layout->addWidget(styledBar);
 
-    // QScrollArea *scrollArea = new QScrollArea(m_modeWidget);
-    // scrollArea->setFrameShape(QFrame::NoFrame);
-    // layout->addWidget(scrollArea);
-    // scrollArea->setWidget(m_welcomePage);
-    // scrollArea->setWidgetResizable(true);
+    QScrollArea *scrollArea = new QScrollArea(m_modeWidget);
+    scrollArea->setFrameShape(QFrame::NoFrame);
+    scrollArea->setWidgetResizable(true);
 
-    QWidget *container = QWidget::createWindowContainer(m_welcomePage, m_modeWidget);
+    QWidget *container = QWidget::createWindowContainer(m_welcomePage, scrollArea);
     container->setMinimumSize(QSize(880, 548));
-    layout->addWidget(container);
+    scrollArea->setWidget(container);
     m_modeWidget->setLayout(layout);
+    layout->addWidget(scrollArea);
 
     connect(PluginManager::instance(), SIGNAL(objectAdded(QObject*)), SLOT(welcomePluginAdded(QObject*)));