3 files changed, 43 insertions, 6 deletions
diff --git a/src/webenginewidgets/api/qwebenginepage.cpp b/src/webenginewidgets/api/qwebenginepage.cpp
index 1a3cf5dde..d05a43d0d 100644
--- a/src/webenginewidgets/api/qwebenginepage.cpp
+++ b/src/webenginewidgets/api/qwebenginepage.cpp
@@ -58,6 +58,15 @@ QWebEnginePagePrivate::QWebEnginePagePrivate()
 
 QWebEnginePagePrivate::~QWebEnginePagePrivate()
 {
+    // "Cancel" pending callbacks by calling them with an invalid value.
+    // This guarantees that each callback is called exactly once.
+    Q_FOREACH (QExplicitlySharedDataPointer<VariantCallback> callback, m_variantCallbacks)
+        (*callback)(QVariant());
+    m_variantCallbacks.clear();
+    Q_FOREACH (QExplicitlySharedDataPointer<StringCallback> callback, m_stringCallbacks)
+        (*callback)(QString());
+    m_stringCallbacks.clear();
+
     delete history;
 }
 
@@ -148,17 +157,20 @@ void QWebEnginePagePrivate::close()
 
 void QWebEnginePagePrivate::didRunJavaScript(const QVariant& result, quint64 requestId)
 {
-    (*m_variantCallbacks.take(requestId))(result);
+    if (QExplicitlySharedDataPointer<VariantCallback> callback = m_variantCallbacks.take(requestId))
+        (*callback)(result);
 }
 
 void QWebEnginePagePrivate::didFetchDocumentMarkup(const QString& result, quint64 requestId)
 {
-    (*m_stringCallbacks.take(requestId))(result);
+    if (QExplicitlySharedDataPointer<StringCallback> callback = m_stringCallbacks.take(requestId))
+        (*callback)(result);
 }
 
 void QWebEnginePagePrivate::didFetchDocumentInnerText(const QString& result, quint64 requestId)
 {
-    (*m_stringCallbacks.take(requestId))(result);
+    if (QExplicitlySharedDataPointer<StringCallback> callback = m_stringCallbacks.take(requestId))
+        (*callback)(result);
 }
 
 void QWebEnginePagePrivate::updateAction(QWebEnginePage::WebAction action) const
diff --git a/tests/auto/widgets/qwebengineframe/tst_qwebengineframe.cpp b/tests/auto/widgets/qwebengineframe/tst_qwebengineframe.cpp
index dd78a4076..99ad21152 100644
--- a/tests/auto/widgets/qwebengineframe/tst_qwebengineframe.cpp
+++ b/tests/auto/widgets/qwebengineframe/tst_qwebengineframe.cpp
@@ -58,6 +58,7 @@ private Q_SLOTS:
     void javaScriptWindowObjectCleared_data();
     void javaScriptWindowObjectCleared();
     void javaScriptWindowObjectClearedOnEvaluate();
+    void asyncAndDelete();
     void earlyToHtml();
     void setHtml();
     void setHtmlWithImageResource();
@@ -400,6 +401,22 @@ void tst_QWebEngineFrame::javaScriptWindowObjectClearedOnEvaluate()
 #endif
 }
 
+void tst_QWebEngineFrame::asyncAndDelete()
+{
+    QWebEnginePage *page = new QWebEnginePage;
+    CallbackSpy<QString> plainTextSpy;
+    CallbackSpy<QString> htmlSpy;
+    page->toPlainText(ref(plainTextSpy));
+    page->toHtml(ref(htmlSpy));
+
+    delete page;
+    // Pending callbacks should be called with an empty value in the page's destructor.
+    QCOMPARE(plainTextSpy.waitForResult(), QString());
+    QVERIFY(plainTextSpy.wasCalled());
+    QCOMPARE(htmlSpy.waitForResult(), QString());
+    QVERIFY(htmlSpy.wasCalled());
+}
+
 void tst_QWebEngineFrame::earlyToHtml()
 {
     QString html("<html><head></head><body></body></html>");
diff --git a/tests/auto/widgets/util.h b/tests/auto/widgets/util.h
index e5e991f89..a9a3d487c 100644
--- a/tests/auto/widgets/util.h
+++ b/tests/auto/widgets/util.h
@@ -93,24 +93,32 @@ public:
     // Tells tr1::ref the result of void operator()(const T &result) when decltype isn't available.
     typedef void result_type;
 
-    CallbackSpy() {
+    CallbackSpy() : called(false) {
         timeoutTimer.setSingleShot(true);
         QObject::connect(&timeoutTimer, SIGNAL(timeout()), &eventLoop, SLOT(quit()));
     }
 
     T waitForResult() {
-        timeoutTimer.start(10000);
-        eventLoop.exec();
+        if (!called) {
+            timeoutTimer.start(10000);
+            eventLoop.exec();
+        }
         return result;
     }
 
+    bool wasCalled() const {
+        return called;
+    }
+
     void operator()(const T &result) {
         this->result = result;
+        called = true;
         eventLoop.quit();
     }
 
 private:
     Q_DISABLE_COPY(CallbackSpy)
+    bool called;
     QTimer timeoutTimer;
     QEventLoop eventLoop;
     T result;