qtquick: Fix crash when mouse receiver gets deleted

Happened when double clicking a tab

src/qtquick/views/TabBar_qtquick.cpp

@@ -126,6 +126,9 @@ bool TabBar_qtquick::event(QEvent *ev)
                 m_tabBar->onMousePress(me->pos());
             else
                 m_tabBar->onMouseDoubleClick(me->pos());
+
+            // Don't call base class, it might have been deleted
+            return true;
         }
 
         break;

src/qtquick/views/View_qtquick.cpp

@@ -80,7 +80,14 @@ public:
 
         // Finally send the event
         m_eventTarget->setProperty("cursorPosition", m_eventSource->property("cursorPosition"));
+        QPointer<QObject> lifeGuard(this);
         qGuiApp->sendEvent(m_eventTarget, me);
+
+        if (!lifeGuard) {
+            // m_eventTarget was deleted, and so was "this"
+            return true;
+        }
+
         m_eventTarget->setProperty("cursorPosition", CursorPosition_Undefined);
 
         return false;