[UI-side compositing] Cannot grab the scrubber to scroll to the end o…

…f a long page (build log) https://bugs.webkit.org/show_bug.cgi?id=259167 rdar://112154989 Reviewed by Simon Fraser. After https://commits.webkit.org/265731@main removed NSScrollerImps in the web process, when ScrollbarThemeMac::minimumThumbLength would query the scrollbar map, it wouldn't be able to find the NSScrollerImp, so it would return 0. This resulted in users not being able to drag the scrollbar. To resolve this, plumb the knobMinLength property to the web process, where it is tracked by RemoteScrollbarsController. * Source/WebCore/page/scrolling/AsyncScrollingCoordinator.cpp: (WebCore::AsyncScrollingCoordinator::requestScrollToPosition): (WebCore::AsyncScrollingCoordinator::scrollingTreeNodeScrollbarMinimumThumbLengthDidChange): * Source/WebCore/page/scrolling/AsyncScrollingCoordinator.h: * Source/WebCore/page/scrolling/ScrollingTree.h: (WebCore::ScrollingTree::scrollingTreeNodeScrollbarMinimumThumbLengthDidChange): * Source/WebCore/page/scrolling/ScrollingTreeScrollingNode.cpp: (WebCore::ScrollingTreeScrollingNode::scrollbarMinimumThumbLengthDidChange): * Source/WebCore/page/scrolling/ScrollingTreeScrollingNode.h: * Source/WebCore/page/scrolling/mac/ScrollerMac.mm: (WebCore::ScrollerMac::attach): (WebCore::ScrollerMac::updateScrollbarStyle): * Source/WebCore/platform/Scrollbar.cpp: (WebCore::Scrollbar::minimumThumbLength const): * Source/WebCore/platform/Scrollbar.h: * Source/WebCore/platform/ScrollbarsController.h: (WebCore::ScrollbarsController::setScrollbarMinimumThumbLength): (WebCore::ScrollbarsController::minimumThumbLength): * Source/WebCore/platform/mac/ScrollbarThemeMac.mm: (WebCore::ScrollbarThemeMac::hasThumb): (WebCore::ScrollbarThemeMac::minimumThumbLength): * Source/WebKit/UIProcess/RemoteLayerTree/RemoteScrollingCoordinatorProxy.cpp: (WebKit::RemoteScrollingCoordinatorProxy::scrollingTreeNodeScrollbarMinimumThumbLengthDidChange): * Source/WebKit/UIProcess/RemoteLayerTree/RemoteScrollingCoordinatorProxy.h: * Source/WebKit/UIProcess/RemoteLayerTree/mac/RemoteScrollingTreeMac.h: * Source/WebKit/UIProcess/RemoteLayerTree/mac/RemoteScrollingTreeMac.mm: (WebKit::RemoteScrollingTreeMac::scrollingTreeNodeScrollbarMinimumThumbLengthDidChange): * Source/WebKit/WebProcess/WebPage/RemoteLayerTree/RemoteScrollbarsController.h: * Source/WebKit/WebProcess/WebPage/RemoteLayerTree/RemoteScrollbarsController.mm: (WebKit::RemoteScrollbarsController::setScrollbarMinimumThumbLength): (WebKit::RemoteScrollbarsController::minimumThumbLength): * Source/WebKit/WebProcess/WebPage/RemoteLayerTree/RemoteScrollingCoordinator.h: * Source/WebKit/WebProcess/WebPage/RemoteLayerTree/RemoteScrollingCoordinator.messages.in: * Source/WebKit/WebProcess/WebPage/RemoteLayerTree/RemoteScrollingCoordinator.mm: (WebKit::RemoteScrollingCoordinator::scrollingTreeNodeScrollbarMinimumThumbLengthDidChange): Canonical link: https://commits.webkit.org/266124@main
WebKit · Jul 18, 2023 · 0f2ddd2 · 0f2ddd2
1 parent 0728a2a
commit 0f2ddd2
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Showing 21 changed files with 97 additions and 23 deletions.
diff --git a/Source/WebCore/page/LocalFrameView.h b/Source/WebCore/page/LocalFrameView.h
@@ -180,7 +180,7 @@ class LocalFrameView final : public FrameView {
     WEBCORE_EXPORT TiledBacking* tiledBacking() const;
 
     WEBCORE_EXPORT ScrollingNodeID scrollingNodeID() const override;
-    ScrollableArea* scrollableAreaForScrollingNodeID(ScrollingNodeID) const;
+    WEBCORE_EXPORT ScrollableArea* scrollableAreaForScrollingNodeID(ScrollingNodeID) const;
     bool usesAsyncScrolling() const final;
 
     WEBCORE_EXPORT void enterCompositingMode();

diff --git a/Source/WebCore/page/scrolling/AsyncScrollingCoordinator.cpp b/Source/WebCore/page/scrolling/AsyncScrollingCoordinator.cpp
@@ -1173,16 +1173,6 @@ bool AsyncScrollingCoordinator::scrollAnimatorEnabled() const
     return settings.scrollAnimatorEnabled();
 }
 
-void AsyncScrollingCoordinator::scrollingTreeNodeScrollbarVisibilityDidChange(ScrollingNodeID nodeID, ScrollbarOrientation orientation, bool isVisible)
-{
-    auto* frameView = frameViewForScrollingNode(nodeID);
-    if (!frameView)
-        return;
-
-    if (auto* scrollableArea = frameView->scrollableAreaForScrollingNodeID(nodeID))
-        scrollableArea->scrollbarsController().setScrollbarVisibilityState(orientation, isVisible);
-}
-
 } // namespace WebCore
 
 #endif // ENABLE(ASYNC_SCROLLING)
diff --git a/Source/WebCore/page/scrolling/AsyncScrollingCoordinator.h b/Source/WebCore/page/scrolling/AsyncScrollingCoordinator.h
@@ -75,7 +75,6 @@ class AsyncScrollingCoordinator : public ScrollingCoordinator {
 
     WEBCORE_EXPORT void setMouseIsOverContentArea(ScrollableArea&, bool) override;
     WEBCORE_EXPORT void setMouseMovedInContentArea(ScrollableArea&) override;
-    WEBCORE_EXPORT void scrollingTreeNodeScrollbarVisibilityDidChange(ScrollingNodeID, ScrollbarOrientation, bool);
 
 protected:
     WEBCORE_EXPORT AsyncScrollingCoordinator(Page*);
@@ -95,6 +94,7 @@ class AsyncScrollingCoordinator : public ScrollingCoordinator {
     void scheduleRenderingUpdate();
 
     bool eventTrackingRegionsDirty() const { return m_eventTrackingRegionsDirty; }
+    WEBCORE_EXPORT LocalFrameView* frameViewForScrollingNode(ScrollingNodeID) const;
 
 private:
     bool isAsyncScrollingCoordinator() const override { return true; }
@@ -173,8 +173,6 @@ class AsyncScrollingCoordinator : public ScrollingCoordinator {
 
     WEBCORE_EXPORT void setMouseIsOverScrollbar(Scrollbar*, bool isOverScrollbar) override;
 
-    LocalFrameView* frameViewForScrollingNode(ScrollingNodeID) const;
-
     void hysterisisTimerFired(PAL::HysteresisState);
 
     std::unique_ptr<ScrollingStateTree> m_scrollingStateTree;

diff --git a/Source/WebCore/page/scrolling/ScrollingTree.h b/Source/WebCore/page/scrolling/ScrollingTree.h
@@ -248,7 +248,8 @@ class ScrollingTree : public ThreadSafeRefCounted<ScrollingTree> {
     WEBCORE_EXPORT Seconds frameDuration();
     WEBCORE_EXPORT Seconds maxAllowableRenderingUpdateDurationForSynchronization();
     WEBCORE_EXPORT virtual void scrollingTreeNodeScrollbarVisibilityDidChange(ScrollingNodeID, ScrollbarOrientation, bool) { };
-
+    WEBCORE_EXPORT virtual void scrollingTreeNodeScrollbarMinimumThumbLengthDidChange(WebCore::ScrollingNodeID, ScrollbarOrientation, int) { };
+
 protected:
     WEBCORE_EXPORT WheelEventHandlingResult handleWheelEventWithNode(const PlatformWheelEvent&, OptionSet<WheelEventProcessingSteps>, ScrollingTreeNode*, EventTargeting = EventTargeting::Propagate);
 

diff --git a/Source/WebCore/page/scrolling/ScrollingTreeScrollingNode.cpp b/Source/WebCore/page/scrolling/ScrollingTreeScrollingNode.cpp
@@ -497,6 +497,11 @@ void ScrollingTreeScrollingNode::scrollbarVisibilityDidChange(ScrollbarOrientati
     scrollingTree().scrollingTreeNodeScrollbarVisibilityDidChange(scrollingNodeID(), orientation, isVisible);
 }
 
+void ScrollingTreeScrollingNode::scrollbarMinimumThumbLengthDidChange(ScrollbarOrientation orientation, int minimumThumbLength)
+{
+    scrollingTree().scrollingTreeNodeScrollbarMinimumThumbLengthDidChange(scrollingNodeID(), orientation, minimumThumbLength);
+}
+
 } // namespace WebCore
 
 #endif // ENABLE(ASYNC_SCROLLING)
diff --git a/Source/WebCore/page/scrolling/ScrollingTreeScrollingNode.h b/Source/WebCore/page/scrolling/ScrollingTreeScrollingNode.h
@@ -136,6 +136,7 @@ class WEBCORE_EXPORT ScrollingTreeScrollingNode : public ScrollingTreeNode {
     virtual String scrollbarStateForOrientation(ScrollbarOrientation) const { return ""_s; }
 
     void scrollbarVisibilityDidChange(ScrollbarOrientation, bool);
+    void scrollbarMinimumThumbLengthDidChange(ScrollbarOrientation, int);
 
 protected:
     ScrollingTreeScrollingNode(ScrollingTree&, ScrollingNodeType, ScrollingNodeID);

diff --git a/Source/WebCore/page/scrolling/mac/ScrollerMac.h b/Source/WebCore/page/scrolling/mac/ScrollerMac.h
@@ -57,7 +57,7 @@ class ScrollerMac {
 
     RetainPtr<NSScrollerImp> takeScrollerImp() { return std::exchange(m_scrollerImp, { }); }
     NSScrollerImp *scrollerImp() { return m_scrollerImp.get(); }
-    void setScrollerImp(NSScrollerImp *imp) { m_scrollerImp = imp; }
+    void setScrollerImp(NSScrollerImp *imp);
     void updateScrollbarStyle();
     void updatePairScrollerImps();
 
@@ -70,8 +70,10 @@ class ScrollerMac {
     void setLastKnownMousePositionInScrollbar(IntPoint position) { m_lastKnownMousePositionInScrollbar = position; }
     IntPoint lastKnownMousePositionInScrollbar() const;
     void visibilityChanged(bool);
+    void updateMinimumKnobLength(int);
     void detach();
 private:
+    int m_minimumKnobLength { 0 };
     bool m_isVisible { false };
     ScrollerPairMac& m_pair;
     const ScrollbarOrientation m_orientation;

diff --git a/Source/WebCore/page/scrolling/mac/ScrollerMac.mm b/Source/WebCore/page/scrolling/mac/ScrollerMac.mm
@@ -330,7 +330,7 @@ - (void)invalidate
 void ScrollerMac::attach()
 {
     m_scrollerImpDelegate = adoptNS([[WebScrollerImpDelegateMac alloc] initWithScroller:this]);
-    m_scrollerImp = [NSScrollerImp scrollerImpWithStyle:nsScrollerStyle(m_pair.scrollbarStyle()) controlSize:nsControlSizeFromScrollbarWidth(m_pair.scrollbarWidthStyle()) horizontal:m_orientation == ScrollbarOrientation::Horizontal replacingScrollerImp:nil];
+    setScrollerImp([NSScrollerImp scrollerImpWithStyle:nsScrollerStyle(m_pair.scrollbarStyle()) controlSize:nsControlSizeFromScrollbarWidth(m_pair.scrollbarWidthStyle()) horizontal:m_orientation == ScrollbarOrientation::Horizontal replacingScrollerImp:nil]);
     [m_scrollerImp setDelegate:m_scrollerImpDelegate.get()];
 }
 
@@ -369,7 +369,7 @@ - (void)invalidate
 
 void ScrollerMac::updateScrollbarStyle()
 {
-    m_scrollerImp = [NSScrollerImp scrollerImpWithStyle:nsScrollerStyle(m_pair.scrollbarStyle()) controlSize:nsControlSizeFromScrollbarWidth(m_pair.scrollbarWidthStyle()) horizontal:m_orientation == ScrollbarOrientation::Horizontal replacingScrollerImp:takeScrollerImp().get()];
+    setScrollerImp([NSScrollerImp scrollerImpWithStyle:nsScrollerStyle(m_pair.scrollbarStyle()) controlSize:nsControlSizeFromScrollbarWidth(m_pair.scrollbarWidthStyle()) horizontal:m_orientation == ScrollbarOrientation::Horizontal replacingScrollerImp:takeScrollerImp().get()]);
     updatePairScrollerImps();
 }
 
@@ -427,6 +427,20 @@ - (void)invalidate
     m_pair.node().scrollbarVisibilityDidChange(m_orientation, isVisible);
 }
 
+void ScrollerMac::updateMinimumKnobLength(int minimumKnobLength)
+{
+    if (m_minimumKnobLength == minimumKnobLength)
+        return;
+    m_minimumKnobLength = minimumKnobLength;
+    m_pair.node().scrollbarMinimumThumbLengthDidChange(m_orientation, m_minimumKnobLength);
+}
+
+void ScrollerMac::setScrollerImp(NSScrollerImp *imp)
+{
+    m_scrollerImp = imp;
+    updateMinimumKnobLength([m_scrollerImp knobMinLength]);
+}
+
 String ScrollerMac::scrollbarState() const
 {
     if (!m_hostLayer || !m_scrollerImp)

diff --git a/Source/WebCore/platform/Scrollbar.cpp b/Source/WebCore/platform/Scrollbar.cpp
@@ -533,4 +533,9 @@ bool Scrollbar::shouldRegisterScrollbar() const
     return m_scrollableArea.scrollbarsController().shouldRegisterScrollbars();
 }
 
+int Scrollbar::minimumThumbLength() const
+{
+    return m_scrollableArea.scrollbarsController().minimumThumbLength(m_orientation);
+}
+
 } // namespace WebCore
diff --git a/Source/WebCore/platform/Scrollbar.h b/Source/WebCore/platform/Scrollbar.h
@@ -142,6 +142,7 @@ class Scrollbar : public Widget {
     float deviceScaleFactor() const;
 
     bool shouldRegisterScrollbar() const;
+    int minimumThumbLength() const;
 
 protected:
     Scrollbar(ScrollableArea&, ScrollbarOrientation, ScrollbarWidth, ScrollbarTheme* = nullptr, bool isCustomScrollbar = false);

diff --git a/Source/WebCore/platform/ScrollbarsController.h b/Source/WebCore/platform/ScrollbarsController.h
@@ -96,6 +96,9 @@ class ScrollbarsController {
     WEBCORE_EXPORT virtual bool shouldDrawIntoScrollbarLayer(Scrollbar&) const { return true; }
     WEBCORE_EXPORT virtual bool shouldRegisterScrollbars() const { return true; }
 
+    WEBCORE_EXPORT virtual void setScrollbarMinimumThumbLength(WebCore::ScrollbarOrientation, int) { }
+    WEBCORE_EXPORT virtual int minimumThumbLength(WebCore::ScrollbarOrientation) { return 0; }
+
 private:
     ScrollableArea& m_scrollableArea;
     bool m_scrollbarAnimationsUnsuspendedByUserInteraction { true };

diff --git a/Source/WebCore/platform/mac/ScrollbarThemeMac.mm b/Source/WebCore/platform/mac/ScrollbarThemeMac.mm
@@ -438,9 +438,12 @@ static IntRect buttonRepaintRect(const IntRect& buttonRect, ScrollbarOrientation
 
 int ScrollbarThemeMac::minimumThumbLength(Scrollbar& scrollbar)
 {
-    BEGIN_BLOCK_OBJC_EXCEPTIONS
-    return [scrollbarMap().get(&scrollbar) knobMinLength];
-    END_BLOCK_OBJC_EXCEPTIONS
+    if (scrollbar.shouldRegisterScrollbar()) {
+        BEGIN_BLOCK_OBJC_EXCEPTIONS
+        return [scrollbarMap().get(&scrollbar) knobMinLength];
+        END_BLOCK_OBJC_EXCEPTIONS
+    } else
+        return scrollbar.minimumThumbLength();
 }
 
 static bool shouldCenterOnThumb(const PlatformMouseEvent& evt)

diff --git a/Source/WebKit/UIProcess/RemoteLayerTree/RemoteScrollingCoordinatorProxy.cpp b/Source/WebKit/UIProcess/RemoteLayerTree/RemoteScrollingCoordinatorProxy.cpp
@@ -434,6 +434,11 @@ void RemoteScrollingCoordinatorProxy::scrollingTreeNodeScrollbarVisibilityDidCha
     m_webPageProxy.send(Messages::RemoteScrollingCoordinator::ScrollingTreeNodeScrollbarVisibilityDidChange(nodeID, orientation, isVisible));
 }
 
+void RemoteScrollingCoordinatorProxy::scrollingTreeNodeScrollbarMinimumThumbLengthDidChange(WebCore::ScrollingNodeID nodeID, ScrollbarOrientation orientation, int minimumThumbLength)
+{
+    m_webPageProxy.send(Messages::RemoteScrollingCoordinator::ScrollingTreeNodeScrollbarMinimumThumbLengthDidChange(nodeID, orientation, minimumThumbLength));
+}
+
 } // namespace WebKit
 
 #endif // ENABLE(UI_SIDE_COMPOSITING)
diff --git a/Source/WebKit/UIProcess/RemoteLayerTree/RemoteScrollingCoordinatorProxy.h b/Source/WebKit/UIProcess/RemoteLayerTree/RemoteScrollingCoordinatorProxy.h
@@ -165,6 +165,7 @@ class RemoteScrollingCoordinatorProxy : public CanMakeWeakPtr<RemoteScrollingCoo
     void sendScrollingTreeNodeDidScroll();
 
     void scrollingTreeNodeScrollbarVisibilityDidChange(WebCore::ScrollingNodeID, WebCore::ScrollbarOrientation, bool);
+    void scrollingTreeNodeScrollbarMinimumThumbLengthDidChange(WebCore::ScrollingNodeID, WebCore::ScrollbarOrientation, int);
 
 protected:
     RemoteScrollingTree* scrollingTree() const { return m_scrollingTree.get(); }

diff --git a/Source/WebKit/UIProcess/RemoteLayerTree/mac/RemoteScrollingTreeMac.h b/Source/WebKit/UIProcess/RemoteLayerTree/mac/RemoteScrollingTreeMac.h
@@ -47,6 +47,7 @@ class RemoteScrollingTreeMac final : public RemoteScrollingTree {
     virtual ~RemoteScrollingTreeMac();
 
     void scrollingTreeNodeScrollbarVisibilityDidChange(WebCore::ScrollingNodeID, ScrollbarOrientation, bool) override;
+    void scrollingTreeNodeScrollbarMinimumThumbLengthDidChange(WebCore::ScrollingNodeID, ScrollbarOrientation, int) override;
 
 private:
     void handleWheelEventPhase(WebCore::ScrollingNodeID, WebCore::PlatformWheelEventPhase) override;

diff --git a/Source/WebKit/UIProcess/RemoteLayerTree/mac/RemoteScrollingTreeMac.mm b/Source/WebKit/UIProcess/RemoteLayerTree/mac/RemoteScrollingTreeMac.mm
@@ -518,6 +518,14 @@ static bool layerEventRegionContainsPoint(CALayer *layer, CGPoint localPoint)
     });
 }
 
+void RemoteScrollingTreeMac::scrollingTreeNodeScrollbarMinimumThumbLengthDidChange(ScrollingNodeID nodeID, ScrollbarOrientation orientation, int minimumThumbLength)
+{
+    RunLoop::main().dispatch([strongThis = Ref { *this }, nodeID, orientation, minimumThumbLength] {
+        if (auto* scrollingCoordinatorProxy = strongThis->scrollingCoordinatorProxy())
+            scrollingCoordinatorProxy->scrollingTreeNodeScrollbarMinimumThumbLengthDidChange(nodeID, orientation, minimumThumbLength);
+    });
+}
+
 } // namespace WebKit
 
 #endif // PLATFORM(MAC) && ENABLE(UI_SIDE_COMPOSITING)
diff --git a/Source/WebKit/WebProcess/WebPage/RemoteLayerTree/RemoteScrollbarsController.h b/Source/WebKit/WebProcess/WebPage/RemoteLayerTree/RemoteScrollbarsController.h
@@ -49,13 +49,18 @@ class RemoteScrollbarsController final : public WebCore::ScrollbarsController {
     void mouseExitedScrollbar(WebCore::Scrollbar*) const final;
     bool shouldScrollbarParticipateInHitTesting(WebCore::Scrollbar*) final;
 
+    void setScrollbarMinimumThumbLength(WebCore::ScrollbarOrientation, int) final;
     void setScrollbarVisibilityState(WebCore::ScrollbarOrientation, bool) final;
     bool shouldDrawIntoScrollbarLayer(WebCore::Scrollbar&) const final;
     bool shouldRegisterScrollbars() const final { return scrollableArea().isListBox(); }
+    int minimumThumbLength(WebCore::ScrollbarOrientation) final;
 
 private:
     bool m_horizontalOverlayScrollbarIsVisible { false };
     bool m_verticalOverlayScrollbarIsVisible { false };
+
+    int m_horizontalMinimumThumbLength { 0 };
+    int m_verticalMinimumThumbLength { 0 };
     ThreadSafeWeakPtr<WebCore::ScrollingCoordinator> m_coordinator;
 };
 

diff --git a/Source/WebKit/WebProcess/WebPage/RemoteLayerTree/RemoteScrollbarsController.mm b/Source/WebKit/WebProcess/WebPage/RemoteLayerTree/RemoteScrollbarsController.mm
@@ -94,5 +94,18 @@
     return scrollbar.isCustomScrollbar() || scrollbar.isMockScrollbar();
 }
 
+void RemoteScrollbarsController::setScrollbarMinimumThumbLength(WebCore::ScrollbarOrientation orientation, int minimumThumbLength)
+{
+    if (orientation == WebCore::ScrollbarOrientation::Horizontal)
+        m_horizontalMinimumThumbLength = minimumThumbLength;
+    else
+        m_verticalMinimumThumbLength = minimumThumbLength;
+}
+
+int RemoteScrollbarsController::minimumThumbLength(WebCore::ScrollbarOrientation orientation)
+{
+    return orientation == WebCore::ScrollbarOrientation::Horizontal ? m_horizontalMinimumThumbLength : m_verticalMinimumThumbLength;
+}
+
 }
 #endif // PLATFORM(MAC)
diff --git a/Source/WebKit/WebProcess/WebPage/RemoteLayerTree/RemoteScrollingCoordinator.h b/Source/WebKit/WebProcess/WebPage/RemoteLayerTree/RemoteScrollingCoordinator.h
@@ -97,6 +97,7 @@ class RemoteScrollingCoordinator final : public WebCore::AsyncScrollingCoordinat
     void startDeferringScrollingTestCompletionForNode(WebCore::ScrollingNodeID, WebCore::WheelEventTestMonitor::DeferReason);
     void stopDeferringScrollingTestCompletionForNode(WebCore::ScrollingNodeID, WebCore::WheelEventTestMonitor::DeferReason);
     void scrollingTreeNodeScrollbarVisibilityDidChange(WebCore::ScrollingNodeID, WebCore::ScrollbarOrientation, bool);
+    void scrollingTreeNodeScrollbarMinimumThumbLengthDidChange(WebCore::ScrollingNodeID nodeID, WebCore::ScrollbarOrientation orientation, int minimumThumbLength);
 
     WebCore::WheelEventHandlingResult handleWheelEventForScrolling(const WebCore::PlatformWheelEvent&, WebCore::ScrollingNodeID, std::optional<WebCore::WheelScrollGestureState>) override;
 

diff --git a/Source/WebKit/WebProcess/WebPage/RemoteLayerTree/RemoteScrollingCoordinator.messages.in b/Source/WebKit/WebProcess/WebPage/RemoteLayerTree/RemoteScrollingCoordinator.messages.in
@@ -32,6 +32,7 @@ messages -> RemoteScrollingCoordinator {
     StartDeferringScrollingTestCompletionForNode(uint64_t nodeID, WebCore::WheelEventTestMonitor::DeferReason reason);
     StopDeferringScrollingTestCompletionForNode(uint64_t nodeID, WebCore::WheelEventTestMonitor::DeferReason reason);
     ScrollingTreeNodeScrollbarVisibilityDidChange(uint64_t nodeID, enum:uint8_t WebCore::ScrollbarOrientation orientation, bool isVisible);
+    ScrollingTreeNodeScrollbarMinimumThumbLengthDidChange(uint64_t nodeID, enum:uint8_t WebCore::ScrollbarOrientation orientation, int minimumThumbLength);
 }
 
 #endif // ENABLE(ASYNC_SCROLLING)
diff --git a/Source/WebKit/WebProcess/WebPage/RemoteLayerTree/RemoteScrollingCoordinator.mm b/Source/WebKit/WebProcess/WebPage/RemoteLayerTree/RemoteScrollingCoordinator.mm
@@ -44,6 +44,7 @@
 #import <WebCore/Page.h>
 #import <WebCore/RenderLayerCompositor.h>
 #import <WebCore/RenderView.h>
+#import <WebCore/ScrollbarsController.h>
 #import <WebCore/ScrollingStateFrameScrollingNode.h>
 #import <WebCore/ScrollingTreeFixedNodeCocoa.h>
 #import <WebCore/ScrollingTreeStickyNodeCocoa.h>
@@ -186,9 +187,24 @@
     return WheelEventHandlingResult::handled();
 }
 
-void RemoteScrollingCoordinator::scrollingTreeNodeScrollbarVisibilityDidChange(ScrollingNodeID nodeID, WebCore::ScrollbarOrientation orientation, bool isVisible)
+void RemoteScrollingCoordinator::scrollingTreeNodeScrollbarVisibilityDidChange(ScrollingNodeID nodeID, ScrollbarOrientation orientation, bool isVisible)
 {
-    AsyncScrollingCoordinator::scrollingTreeNodeScrollbarVisibilityDidChange(nodeID, orientation, isVisible);
+    auto* frameView = frameViewForScrollingNode(nodeID);
+    if (!frameView)
+        return;
+
+    if (auto* scrollableArea = frameView->scrollableAreaForScrollingNodeID(nodeID))
+        scrollableArea->scrollbarsController().setScrollbarVisibilityState(orientation, isVisible);
+}
+
+void RemoteScrollingCoordinator::scrollingTreeNodeScrollbarMinimumThumbLengthDidChange(ScrollingNodeID nodeID, ScrollbarOrientation orientation, int minimumThumbLength)
+{
+    auto* frameView = frameViewForScrollingNode(nodeID);
+    if (!frameView)
+        return;
+
+    if (auto* scrollableArea = frameView->scrollableAreaForScrollingNodeID(nodeID))
+        scrollableArea->scrollbarsController().setScrollbarMinimumThumbLength(orientation, minimumThumbLength);
 }
 
 } // namespace WebKit