[WebView] Another approach to window.onbeforeunload handling

Don't try to load empty url just to check for beforeunload event.
Explicitly evaluate the window.onbeforeunload function instead.

src/lib/tools/closedtabsmanager.cpp

@@ -47,7 +47,6 @@ bool ClosedTabsManager::isClosedTabAvailable()
     return !m_closedTabs.isEmpty();
 }
 
-
 ClosedTabsManager::Tab ClosedTabsManager::takeLastClosedTab()
 {
     Tab tab;

src/lib/webview/tabwidget.cpp

@@ -472,13 +472,9 @@ void TabWidget::closeTab(int index, bool force)
     m_closedTabsManager->saveView(webTab, index);
 
     // window.onbeforeunload handling
-    if (!webView->page()->mainFrame()->evaluateJavaScript("window.onbeforeunload===null").toBool()) {
-        webView->load(QUrl());
-        if (webView->url() != QUrl()) {
-            // We are not closing, let's remove the tab from history
-            m_closedTabsManager->takeLastClosedTab();
-            return;
-        }
+    if (!webView->onBeforeUnload()) {
+        m_closedTabsManager->takeLastClosedTab();
+        return;
     }
 
     m_locationBars->removeWidget(webView->webTab()->locationBar());

src/lib/webview/webview.cpp

@@ -234,6 +234,17 @@ QWebElement WebView::activeElement() const
     return page()->mainFrame()->hitTestContent(activeRect.center()).element();
 }
 
+bool WebView::onBeforeUnload()
+{
+    const QString res = page()->mainFrame()->evaluateJavaScript("window.onbeforeunload(new Event(\"beforeunload\"))").toString();
+
+    if (!res.isEmpty()) {
+        return page()->javaScriptConfirm(page()->mainFrame(), res);
+    }
+
+    return true;
+}
+
 bool WebView::isUrlValid(const QUrl &url)
 {
     // Valid url must have scheme and actually contains something (therefore scheme:// is invalid)

src/lib/webview/webview.h

@@ -51,6 +51,9 @@ public:
     bool hasRss() const;
     QWebElement activeElement() const;
 
+    // Executes window.onbeforeunload, returns true if view can be closed
+    bool onBeforeUnload();
+
     void addNotification(QWidget* notif);
     bool eventFilter(QObject* obj, QEvent* event);