Merge remote-tracking branch 'origin/5.15.0' into 5.15

Change-Id: I916838caf8c981d5dac876631a6e510ed2ffbe0e

16 files changed, 154 insertions, 47 deletions

diff --git a/src/3rdparty b/src/3rdparty
-Subproject 757b9f459d3770644ad83d2faf26a7539c65023
+Subproject 6f260e5b2f717b9977045419f12c7c35d31f9a9
diff --git a/src/buildtools/configure.json b/src/buildtools/configure.json
index 1298ab916..a80ef32eb 100644
--- a/src/buildtools/configure.json
+++ b/src/buildtools/configure.json
@@ -34,8 +34,9 @@
         },
         "webengine-xkbcommon": {
             "label": "xkbcommon",
+            "headers": "xkbcommon/xkbcommon.h",
             "sources": [
-                { "type": "pkgConfig", "args": "xkbcommon" }
+                "-lxkbcommon"
             ]
         },
         "webengine-xcomposite": {
@@ -296,13 +297,6 @@
                 ]
             }
         },
-        "webengine-xkbcommon": {
-            "label": "system xkbcommon",
-            "type": "compile",
-            "test": {
-                "include": "xkbcommon/xkbcommon.h"
-            }
-        },
         "webengine-ninja": {
             "label": "system ninja",
             "type": "detectNinja"
@@ -455,7 +449,7 @@
         },
         "webengine-system-xkbcommon": {
             "label": "xkbcommon",
-            "condition": "libs.webengine-xkbcommon && tests.webengine-xkbcommon",
+            "condition": "libs.webengine-xkbcommon",
             "output": [ "privateFeature" ]
         },
         "webengine-system-xcomposite": {
diff --git a/src/core/render_widget_host_view_qt.cpp b/src/core/render_widget_host_view_qt.cpp
index c99c560a3..0af26314a 100644
--- a/src/core/render_widget_host_view_qt.cpp
+++ b/src/core/render_widget_host_view_qt.cpp
@@ -1530,7 +1530,21 @@ void RenderWidgetHostViewQt::WheelEventAck(const blink::WebMouseWheelEvent &even
         m_mouseWheelPhaseHandler.AddPhaseIfNeededAndScheduleEndEvent(webEvent, false);
         host()->ForwardWheelEvent(webEvent);
     }
-    // TODO: We could forward unhandled wheelevents to our parent.
+}
+
+void RenderWidgetHostViewQt::GestureEventAck(const blink::WebGestureEvent &event, content::InputEventAckState ack_result)
+{
+    // Forward unhandled scroll events back as wheel events
+    if (event.GetType() != blink::WebInputEvent::kGestureScrollUpdate)
+        return;
+    switch (ack_result) {
+    case content::INPUT_EVENT_ACK_STATE_NOT_CONSUMED:
+    case content::INPUT_EVENT_ACK_STATE_NO_CONSUMER_EXISTS:
+        WebEventFactory::sendUnhandledWheelEvent(event, delegate());
+        break;
+    default:
+        break;
+    }
 }
 
 content::MouseWheelPhaseHandler *RenderWidgetHostViewQt::GetMouseWheelPhaseHandler()
diff --git a/src/core/render_widget_host_view_qt.h b/src/core/render_widget_host_view_qt.h
index 41ce50b34..a07d21468 100644
--- a/src/core/render_widget_host_view_qt.h
+++ b/src/core/render_widget_host_view_qt.h
@@ -155,6 +155,7 @@ public:
     void DidCreateNewRendererCompositorFrameSink(viz::mojom::CompositorFrameSinkClient* renderer_compositor_frame_sink) override;
     void SubmitCompositorFrame(const viz::LocalSurfaceId&, viz::CompositorFrame, base::Optional<viz::HitTestRegionList>) override;
     void WheelEventAck(const blink::WebMouseWheelEvent &event, content::InputEventAckState ack_result) override;
+    void GestureEventAck(const blink::WebGestureEvent &event, content::InputEventAckState ack_result) override;
     content::MouseWheelPhaseHandler *GetMouseWheelPhaseHandler() override;
     viz::ScopedSurfaceIdAllocator DidUpdateVisualProperties(const cc::RenderFrameMetadata &metadata) override;
     void OnDidUpdateVisualPropertiesComplete(const cc::RenderFrameMetadata &metadata);
diff --git a/src/core/render_widget_host_view_qt_delegate.h b/src/core/render_widget_host_view_qt_delegate.h
index 4ee790ce9..46f1802a6 100644
--- a/src/core/render_widget_host_view_qt_delegate.h
+++ b/src/core/render_widget_host_view_qt_delegate.h
@@ -58,12 +58,13 @@
 
 QT_BEGIN_NAMESPACE
 class QEvent;
+class QInputMethodEvent;
 class QSGLayer;
 class QSGNode;
 class QSGRectangleNode;
 class QSGTexture;
 class QVariant;
-class QInputMethodEvent;
+class QWheelEvent;
 
 class QSGImageNode;
 
@@ -111,6 +112,7 @@ public:
     virtual void setInputMethodHints(Qt::InputMethodHints hints) = 0;
     virtual void setClearColor(const QColor &color) = 0;
     virtual bool copySurface(const QRect &, const QSize &, QImage &) = 0;
+    virtual void unhandledWheelEvent(QWheelEvent *) {}
 };
 
 } // namespace QtWebEngineCore
diff --git a/src/core/web_contents_adapter_client.h b/src/core/web_contents_adapter_client.h
index 250801f51..04df99f0e 100644
--- a/src/core/web_contents_adapter_client.h
+++ b/src/core/web_contents_adapter_client.h
@@ -469,7 +469,10 @@ public:
     virtual void loadFinished(bool success, const QUrl &url, bool isErrorPage = false, int errorCode = 0, const QString &errorDescription = QString()) = 0;
     virtual void focusContainer() = 0;
     virtual void unhandledKeyEvent(QKeyEvent *event) = 0;
-    virtual void adoptNewWindow(QSharedPointer<WebContentsAdapter> newWebContents, WindowOpenDisposition disposition, bool userGesture, const QRect & initialGeometry, const QUrl &targetUrl) = 0;
+    virtual QSharedPointer<WebContentsAdapter>
+    adoptNewWindow(QSharedPointer<WebContentsAdapter> newWebContents,
+                   WindowOpenDisposition disposition, bool userGesture,
+                   const QRect &initialGeometry, const QUrl &targetUrl) = 0;
     virtual bool isBeingAdopted() = 0;
     virtual void close() = 0;
     virtual void windowCloseRejected() = 0;
diff --git a/src/core/web_contents_delegate_qt.cpp b/src/core/web_contents_delegate_qt.cpp
index fada874a3..216e4faf1 100644
--- a/src/core/web_contents_delegate_qt.cpp
+++ b/src/core/web_contents_delegate_qt.cpp
@@ -663,14 +663,17 @@ void WebContentsDelegateQt::overrideWebPreferences(content::WebContents *webCont
     m_viewClient->webEngineSettings()->overrideWebPreferences(webContents, webPreferences);
 }
 
-QWeakPointer<WebContentsAdapter> WebContentsDelegateQt::createWindow(std::unique_ptr<content::WebContents> new_contents, WindowOpenDisposition disposition, const gfx::Rect& initial_pos, bool user_gesture)
+QSharedPointer<WebContentsAdapter>
+WebContentsDelegateQt::createWindow(std::unique_ptr<content::WebContents> new_contents,
+                                    WindowOpenDisposition disposition, const gfx::Rect &initial_pos,
+                                    bool user_gesture)
 {
     QSharedPointer<WebContentsAdapter> newAdapter = QSharedPointer<WebContentsAdapter>::create(std::move(new_contents));
 
-    m_viewClient->adoptNewWindow(newAdapter, static_cast<WebContentsAdapterClient::WindowOpenDisposition>(disposition), user_gesture, toQt(initial_pos), m_initialTargetUrl);
-
-    // If the client didn't reference the adapter, it will be deleted now, and the weak pointer zeroed.
-    return newAdapter;
+    return m_viewClient->adoptNewWindow(
+            std::move(newAdapter),
+            static_cast<WebContentsAdapterClient::WindowOpenDisposition>(disposition), user_gesture,
+            toQt(initial_pos), m_initialTargetUrl);
 }
 
 void WebContentsDelegateQt::allowCertificateError(const QSharedPointer<CertificateErrorController> &errorController)
@@ -797,6 +800,15 @@ bool WebContentsDelegateQt::TakeFocus(content::WebContents *source, bool reverse
     return m_viewClient->passOnFocus(reverse);
 }
 
+void WebContentsDelegateQt::ContentsZoomChange(bool zoom_in)
+{
+    WebContentsAdapter *adapter = webContentsAdapter();
+    if (zoom_in)
+        adapter->setZoomFactor(adapter->currentZoomFactor() + 0.1f);
+    else
+        adapter->setZoomFactor(adapter->currentZoomFactor() - 0.1f);
+}
+
 FaviconManager *WebContentsDelegateQt::faviconManager()
 {
     return m_faviconManager.data();
diff --git a/src/core/web_contents_delegate_qt.h b/src/core/web_contents_delegate_qt.h
index f32b02caf..bfef9a1df 100644
--- a/src/core/web_contents_delegate_qt.h
+++ b/src/core/web_contents_delegate_qt.h
@@ -148,6 +148,7 @@ public:
     void RegisterProtocolHandler(content::WebContents* web_contents, const std::string& protocol, const GURL& url, bool user_gesture) override;
     void UnregisterProtocolHandler(content::WebContents* web_contents, const std::string& protocol, const GURL& url, bool user_gesture) override;
     bool TakeFocus(content::WebContents *source, bool reverse) override;
+    void ContentsZoomChange(bool zoom_in) override;
 
     // WebContentsObserver overrides
     void RenderFrameCreated(content::RenderFrameHost *render_frame_host) override;
@@ -200,7 +201,10 @@ public:
     base::WeakPtr<WebContentsDelegateQt> AsWeakPtr() { return m_weakPtrFactory.GetWeakPtr(); }
 
 private:
-    QWeakPointer<WebContentsAdapter> createWindow(std::unique_ptr<content::WebContents> new_contents, WindowOpenDisposition disposition, const gfx::Rect& initial_pos, bool user_gesture);
+    QSharedPointer<WebContentsAdapter>
+    createWindow(std::unique_ptr<content::WebContents> new_contents,
+                 WindowOpenDisposition disposition, const gfx::Rect &initial_pos,
+                 bool user_gesture);
     void EmitLoadStarted(const QUrl &url, bool isErrorPage = false);
     void EmitLoadFinished(bool success, const QUrl &url, bool isErrorPage = false, int errorCode = 0, const QString &errorDescription = QString());
     void EmitLoadCommitted();
diff --git a/src/core/web_event_factory.cpp b/src/core/web_event_factory.cpp
index f37cce6c7..9824b3f37 100644
--- a/src/core/web_event_factory.cpp
+++ b/src/core/web_event_factory.cpp
@@ -71,6 +71,8 @@
 #include "ui/events/keycodes/dom/keycode_converter.h"
 #include "ui/events/keycodes/keyboard_code_conversion.h"
 
+#include "render_widget_host_view_qt_delegate.h"
+
 #include <QtGui/private/qtgui-config_p.h>
 
 #include <QCoreApplication>
@@ -84,6 +86,8 @@
 #endif
 #include <QWheelEvent>
 
+namespace QtWebEngineCore {
+
 using namespace blink;
 
 enum class KeyboardDriver { Unknown, Windows, Cocoa, Xkb, Evdev };
@@ -1306,6 +1310,42 @@ static inline WebInputEvent::Modifiers modifiersForEvent(const QInputEvent* even
     return (WebInputEvent::Modifiers)result;
 }
 
+static inline Qt::KeyboardModifiers keyboardModifiersForModifier(unsigned int modifier)
+{
+    Qt::KeyboardModifiers modifiers = {};
+    if (modifier & WebInputEvent::kControlKey)
+        modifiers |= Qt::ControlModifier;
+    if (modifier & WebInputEvent::kMetaKey)
+        modifiers |= Qt::MetaModifier;
+    if (modifier & WebInputEvent::kShiftKey)
+        modifiers |= Qt::ShiftModifier;
+    if (modifier & WebInputEvent::kAltKey)
+        modifiers |= Qt::AltModifier;
+    if (modifier & WebInputEvent::kIsKeyPad)
+        modifiers |= Qt::KeypadModifier;
+
+    if (keyboardDriver() == KeyboardDriver::Cocoa && !qApp->testAttribute(Qt::AA_MacDontSwapCtrlAndMeta)) {
+        bool controlModifier = modifiers.testFlag(Qt::ControlModifier);
+        bool metaModifier = modifiers.testFlag(Qt::MetaModifier);
+        modifiers.setFlag(Qt::ControlModifier, metaModifier);
+        modifiers.setFlag(Qt::MetaModifier, controlModifier);
+    }
+
+    return modifiers;
+}
+
+static inline Qt::MouseButtons mouseButtonsForModifier(unsigned int modifier)
+{
+    Qt::MouseButtons buttons = {};
+    if (modifier & WebInputEvent::kLeftButtonDown)
+        buttons |= Qt::LeftButton;
+    if (modifier & WebInputEvent::kRightButtonDown)
+        buttons |= Qt::RightButton;
+    if (modifier & WebInputEvent::kMiddleButtonDown)
+        buttons |= Qt::MiddleButton;
+    return buttons;
+}
+
 static WebInputEvent::Type webEventTypeForEvent(const QEvent* event)
 {
     switch (event->type()) {
@@ -1471,6 +1511,14 @@ static void setBlinkWheelEventDelta(blink::WebMouseWheelEvent &webEvent)
     webEvent.delta_y = webEvent.wheel_ticks_y * wheelScrollLines * cDefaultQtScrollStep;
 }
 
+static QPoint getWheelEventDelta(const blink::WebGestureEvent &webEvent)
+{
+    static const float cDefaultQtScrollStep = 20.f;
+    static const int wheelScrollLines = QGuiApplication::styleHints()->wheelScrollLines();
+    return QPoint(webEvent.data.scroll_update.delta_x * QWheelEvent::DefaultDeltasPerStep / (wheelScrollLines * cDefaultQtScrollStep),
+                  webEvent.data.scroll_update.delta_y * QWheelEvent::DefaultDeltasPerStep / (wheelScrollLines * cDefaultQtScrollStep));
+}
+
 blink::WebMouseWheelEvent::Phase toBlinkPhase(QWheelEvent *ev)
 {
     switch (ev->phase()) {
@@ -1552,6 +1600,26 @@ bool WebEventFactory::coalesceWebWheelEvent(blink::WebMouseWheelEvent &webEvent,
     return true;
 }
 
+static QPointF toQt(blink::WebFloatPoint p)
+{
+    return QPointF(p.x, p.y);
+}
+
+void WebEventFactory::sendUnhandledWheelEvent(const blink::WebGestureEvent &event,
+                                              RenderWidgetHostViewQtDelegate *delegate)
+{
+    Q_ASSERT(event.GetType() == blink::WebInputEvent::kGestureScrollUpdate);
+
+    QWheelEvent ev(toQt(event.PositionInWidget()),
+                   toQt(event.PositionInScreen()),
+                   QPoint(event.data.scroll_update.delta_x, event.data.scroll_update.delta_y),
+                   getWheelEventDelta(event),
+                   mouseButtonsForModifier(event.GetModifiers()),
+                   keyboardModifiersForModifier(event.GetModifiers()),
+                   Qt::NoScrollPhase, false);
+    delegate->unhandledWheelEvent(&ev);
+}
+
 content::NativeWebKeyboardEvent WebEventFactory::toWebKeyboardEvent(QKeyEvent *ev)
 {
     content::NativeWebKeyboardEvent webKitEvent(reinterpret_cast<gfx::NativeEvent>(ev));
@@ -1686,3 +1754,5 @@ bool WebEventFactory::getEditCommand(QKeyEvent *event, std::string *editCommand)
 
     return false;
 }
+
+} // namespace QtWebEngineCore
diff --git a/src/core/web_event_factory.h b/src/core/web_event_factory.h
index 526202cfb..390502a9d 100644
--- a/src/core/web_event_factory.h
+++ b/src/core/web_event_factory.h
@@ -63,6 +63,10 @@ class QNativeGestureEvent;
 #endif
 QT_END_NAMESPACE
 
+namespace QtWebEngineCore {
+
+class RenderWidgetHostViewQtDelegate;
+
 class WebEventFactory {
 
 public:
@@ -77,9 +81,11 @@ public:
 #endif
     static blink::WebMouseWheelEvent toWebWheelEvent(QWheelEvent *);
     static bool coalesceWebWheelEvent(blink::WebMouseWheelEvent &, QWheelEvent *);
+    static void sendUnhandledWheelEvent(const blink::WebGestureEvent &, RenderWidgetHostViewQtDelegate *);
     static content::NativeWebKeyboardEvent toWebKeyboardEvent(QKeyEvent*);
     static bool getEditCommand(QKeyEvent *event, std::string *editCommand);
 };
 
+} // namespace QtWebEngineCore
 
 #endif // WEB_EVENT_FACTORY_H
diff --git a/src/webengine/api/qquickwebengineview.cpp b/src/webengine/api/qquickwebengineview.cpp
index 7052afe42..4096eb7f6 100644
--- a/src/webengine/api/qquickwebengineview.cpp
+++ b/src/webengine/api/qquickwebengineview.cpp
@@ -547,12 +547,13 @@ void QQuickWebEngineViewPrivate::unhandledKeyEvent(QKeyEvent *event)
         QCoreApplication::sendEvent(q->parentItem(), event);
 }
 
-void QQuickWebEngineViewPrivate::adoptNewWindow(QSharedPointer<WebContentsAdapter> newWebContents, WindowOpenDisposition disposition, bool userGesture, const QRect &, const QUrl &targetUrl)
+QSharedPointer<WebContentsAdapter>
+QQuickWebEngineViewPrivate::adoptNewWindow(QSharedPointer<WebContentsAdapter> newWebContents,
+                                           WindowOpenDisposition disposition, bool userGesture,
+                                           const QRect &, const QUrl &targetUrl)
 {
     Q_Q(QQuickWebEngineView);
     QQuickWebEngineNewViewRequest request;
-    // This increases the ref-count of newWebContents and will tell Chromium
-    // to start loading it and possibly return it to its parent page window.open().
     request.m_adapter = newWebContents;
     request.m_isUserInitiated = userGesture;
     request.m_requestedUrl = targetUrl;
@@ -575,6 +576,8 @@ void QQuickWebEngineViewPrivate::adoptNewWindow(QSharedPointer<WebContentsAdapte
     }
 
     Q_EMIT q->newViewRequested(&request);
+
+    return newWebContents;
 }
 
 bool QQuickWebEngineViewPrivate::isBeingAdopted()
diff --git a/src/webengine/api/qquickwebengineview_p_p.h b/src/webengine/api/qquickwebengineview_p_p.h
index 5c884e36e..e696f6a0c 100644
--- a/src/webengine/api/qquickwebengineview_p_p.h
+++ b/src/webengine/api/qquickwebengineview_p_p.h
@@ -121,7 +121,10 @@ public:
     void loadFinished(bool success, const QUrl &url, bool isErrorPage = false, int errorCode = 0, const QString &errorDescription = QString()) override;
     void focusContainer() override;
     void unhandledKeyEvent(QKeyEvent *event) override;
-    void adoptNewWindow(QSharedPointer<QtWebEngineCore::WebContentsAdapter> newWebContents, WindowOpenDisposition disposition, bool userGesture, const QRect &, const QUrl &targetUrl) override;
+    QSharedPointer<QtWebEngineCore::WebContentsAdapter>
+    adoptNewWindow(QSharedPointer<QtWebEngineCore::WebContentsAdapter> newWebContents,
+                   WindowOpenDisposition disposition, bool userGesture, const QRect &,
+                   const QUrl &targetUrl) override;
     bool isBeingAdopted() override;
     void close() override;
     void windowCloseRejected() override;
diff --git a/src/webenginewidgets/api/qwebenginepage.cpp b/src/webenginewidgets/api/qwebenginepage.cpp
index af98fda0b..4bbddd740 100644
--- a/src/webenginewidgets/api/qwebenginepage.cpp
+++ b/src/webenginewidgets/api/qwebenginepage.cpp
@@ -348,7 +348,10 @@ void QWebEnginePagePrivate::unhandledKeyEvent(QKeyEvent *event)
         QGuiApplication::sendEvent(view->parentWidget(), event);
 }
 
-void QWebEnginePagePrivate::adoptNewWindow(QSharedPointer<WebContentsAdapter> newWebContents, WindowOpenDisposition disposition, bool userGesture, const QRect &initialGeometry, const QUrl &targetUrl)
+QSharedPointer<WebContentsAdapter>
+QWebEnginePagePrivate::adoptNewWindow(QSharedPointer<WebContentsAdapter> newWebContents,
+                                      WindowOpenDisposition disposition, bool userGesture,
+                                      const QRect &initialGeometry, const QUrl &targetUrl)
 {
     Q_Q(QWebEnginePage);
     Q_UNUSED(userGesture);
@@ -356,27 +359,11 @@ void QWebEnginePagePrivate::adoptNewWindow(QSharedPointer<WebContentsAdapter> ne
 
     QWebEnginePage *newPage = q->createWindow(toWindowType(disposition));
     if (!newPage)
-        return;
+        return nullptr;
 
-    if (newPage->d_func() == this) {
-        // If createWindow returns /this/ we must delay the adoption.
-        Q_ASSERT(q == newPage);
-        // WebContents might be null if we just opened a new page for navigation, in that case
-        // avoid referencing newWebContents so that it is deleted and WebContentsDelegateQt::OpenURLFromTab
-        // will fall back to navigating current page.
-        if (newWebContents->webContents()) {
-            QTimer::singleShot(0, q, [this, newPage, newWebContents, initialGeometry] () {
-                adoptNewWindowImpl(newPage, newWebContents, initialGeometry);
-            });
-        }
-    } else {
-        adoptNewWindowImpl(newPage, newWebContents, initialGeometry);
-    }
-}
+    if (!newWebContents->webContents())
+        return newPage->d_func()->adapter; // Reuse existing adapter
 
-void QWebEnginePagePrivate::adoptNewWindowImpl(QWebEnginePage *newPage,
-        const QSharedPointer<WebContentsAdapter> &newWebContents, const QRect &initialGeometry)
-{
     // Mark the new page as being in the process of being adopted, so that a second mouse move event
     // sent by newWebContents->initialize() gets filtered in RenderWidgetHostViewQt::forwardEvent.
     // The first mouse move event is being sent by q->createWindow(). This is necessary because
@@ -394,6 +381,8 @@ void QWebEnginePagePrivate::adoptNewWindowImpl(QWebEnginePage *newPage,
 
     if (!initialGeometry.isEmpty())
         emit newPage->geometryChangeRequested(initialGeometry);
+
+    return newWebContents;
 }
 
 bool QWebEnginePagePrivate::isBeingAdopted()
diff --git a/src/webenginewidgets/api/qwebenginepage_p.h b/src/webenginewidgets/api/qwebenginepage_p.h
index f37413b8e..b4424ec4b 100644
--- a/src/webenginewidgets/api/qwebenginepage_p.h
+++ b/src/webenginewidgets/api/qwebenginepage_p.h
@@ -112,10 +112,10 @@ public:
     void loadFinished(bool success, const QUrl &url, bool isErrorPage = false, int errorCode = 0, const QString &errorDescription = QString()) override;
     void focusContainer() override;
     void unhandledKeyEvent(QKeyEvent *event) override;
-    void adoptNewWindow(QSharedPointer<QtWebEngineCore::WebContentsAdapter> newWebContents, WindowOpenDisposition disposition, bool userGesture, const QRect &initialGeometry, const QUrl &targetUrl) override;
-    void adoptNewWindowImpl(QWebEnginePage *newPage,
-            const QSharedPointer<QtWebEngineCore::WebContentsAdapter> &newWebContents,
-            const QRect &initialGeometry);
+    QSharedPointer<QtWebEngineCore::WebContentsAdapter>
+    adoptNewWindow(QSharedPointer<QtWebEngineCore::WebContentsAdapter> newWebContents,
+                   WindowOpenDisposition disposition, bool userGesture,
+                   const QRect &initialGeometry, const QUrl &targetUrl) override;
     bool isBeingAdopted() override;
     void close() override;
     void windowCloseRejected() override;
diff --git a/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.cpp b/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.cpp
index fdd6d1c4f..66b4cffea 100644
--- a/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.cpp
+++ b/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.cpp
@@ -474,11 +474,16 @@ bool RenderWidgetHostViewQtDelegateWidget::event(QEvent *event)
 
     if (!handled)
         return QQuickWidget::event(event);
-    // Most events are accepted by default, but tablet events are not:
     event->accept();
     return true;
 }
 
+void RenderWidgetHostViewQtDelegateWidget::unhandledWheelEvent(QWheelEvent *ev)
+{
+    if (QWidget *p = parentWidget())
+        qApp->sendEvent(p, ev);
+}
+
 void RenderWidgetHostViewQtDelegateWidget::onWindowPosChanged()
 {
     m_client->visualPropertiesChanged();
diff --git a/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.h b/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.h
index c7783117a..034fdd65c 100644
--- a/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.h
+++ b/src/webenginewidgets/render_widget_host_view_qt_delegate_widget.h
@@ -91,6 +91,7 @@ public:
     void setInputMethodHints(Qt::InputMethodHints) override;
     void setClearColor(const QColor &color) override;
     bool copySurface(const QRect &, const QSize &, QImage &) override;
+    void unhandledWheelEvent(QWheelEvent *ev) override;
 
 protected:
     bool event(QEvent *event) override;