Fix parenting WebPage when created from WebPage::createWindow

Closes #1949

src/lib/webengine/webview.cpp

@@ -124,6 +124,7 @@ void WebView::setPage(WebPage *page)
     }
 
     m_page = page;
+    m_page->setParent(this);
     QWebEngineView::setPage(m_page);
 
     connect(m_page, SIGNAL(privacyChanged(bool)), this, SIGNAL(privacyChanged(bool)));

src/lib/webtab/webtab.cpp

@@ -119,7 +119,7 @@ WebTab::WebTab(BrowserWindow* window)
 
     m_webView = new TabbedWebView(this);
     m_webView->setBrowserWindow(m_window);
-    m_webView->setWebPage(new WebPage(this));
+    m_webView->setWebPage(new WebPage);
     m_webView->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Expanding);
 
     m_locationBar = new LocationBar(m_window);