UI process side scrollbars for UI side compositing on Mac

UI process side scrollbars for UI side compositing on Mac
https://bugs.webkit.org/show_bug.cgi?id=193106

Reviewed by Tim Horton.

Source/WebCore:

* page/FrameView.cpp:
(WebCore::FrameView::paintScrollCorner):
* page/scrolling/AsyncScrollingCoordinator.cpp:
(WebCore::AsyncScrollingCoordinator::frameViewLayoutUpdated):

Pass scrollbar host layers and the dark appearance bit to the scrolling tree.

* page/scrolling/ScrollingCoordinator.cpp:
(WebCore::ScrollingCoordinator::verticalScrollbarLayerForFrameView):
(WebCore::ScrollingCoordinator::horizontalScrollbarLayerForFrameView):
* page/scrolling/ScrollingCoordinator.h:
(WebCore::ScrollableAreaParameters::ScrollableAreaParameters):
(WebCore::ScrollableAreaParameters::operator== const):
* page/scrolling/ScrollingStateFrameScrollingNode.cpp:
(WebCore::ScrollingStateFrameScrollingNode::ScrollingStateFrameScrollingNode):
(WebCore::ScrollingStateFrameScrollingNode::setScrollbarLayers):
* page/scrolling/ScrollingStateFrameScrollingNode.h:
* page/scrolling/ScrollingTreeFrameScrollingNode.h:
* page/scrolling/ScrollingTreeScrollingNode.h:
(WebCore::ScrollingTreeScrollingNode::scrollableAreaSize const):
(WebCore::ScrollingTreeScrollingNode::totalContentsSize const):
(WebCore::ScrollingTreeScrollingNode::useDarkAppearanceForScrollbars const):
(WebCore::ScrollingTreeScrollingNode::lastCommittedScrollPosition const):
* page/scrolling/mac/ScrollingTreeFrameScrollingNodeMac.h:
* platform/ScrollableArea.cpp:
(WebCore::ScrollableArea::useDarkAppearanceForScrollbars const):

Factor into a function as this is used in several places.

* platform/ScrollableArea.h:
* platform/mac/NSScrollerImpDetails.h:
* platform/mac/ScrollAnimatorMac.mm:
(-[WebScrollerImpDelegate effectiveAppearanceForScrollerImp:]):
* platform/mac/ScrollbarThemeMac.h:

Source/WebKit:

This patch implements Mac scrollbars on UI process side using the low level NSScrollerImp/NSScrollerPairImp
SPIs. With this patch scrollbars mostly work for the main frame and also render (but can't be interacted with)
for the subframes.

This is based on the similar code for web process side scrollbars in ScrollAnimatorMac. There is quite a bit of
copy code as there is no way to share nicely. One of these will eventually go away anyway.

* Shared/RemoteLayerTree/RemoteScrollingCoordinatorTransaction.cpp:
(ArgumentCoder<ScrollingStateFrameScrollingNode>::encode):
(ArgumentCoder<ScrollingStateFrameScrollingNode>::decode):
* Shared/WebCoreArgumentCoders.cpp:
(IPC::ArgumentCoder<ScrollableAreaParameters>::encode):
(IPC::ArgumentCoder<ScrollableAreaParameters>::decode):
* UIProcess/RemoteLayerTree/RemoteLayerTreeNode.h:
* UIProcess/RemoteLayerTree/RemoteScrollingCoordinatorProxy.cpp:
(WebKit::RemoteScrollingCoordinatorProxy::connectStateNodeLayers):
(WebKit::RemoteScrollingCoordinatorProxy::handleMouseEvent):
* UIProcess/RemoteLayerTree/RemoteScrollingCoordinatorProxy.h:
* UIProcess/RemoteLayerTree/RemoteScrollingTree.cpp:
(WebKit::RemoteScrollingTree::createScrollingTreeNode):
(WebKit::RemoteScrollingTree::handleMouseEvent):
* UIProcess/RemoteLayerTree/RemoteScrollingTree.h:
* UIProcess/RemoteLayerTree/mac: Added.
* UIProcess/RemoteLayerTree/mac/ScrollerMac.h: Added.

Wraps NSScrollerImp for vertical or horizontal scrollbar.

(WebKit::ScrollerMac::pair):
(WebKit::ScrollerMac::orientation const):
(WebKit::ScrollerMac::hostLayer const):
(WebKit::ScrollerMac::scrollerImp):
* UIProcess/RemoteLayerTree/mac/ScrollerMac.mm: Added.
(-[WKScrollbarPartAnimation initWithScroller:featureToAnimate:animateFrom:animateTo:duration:]):
(-[WKScrollbarPartAnimation startAnimation]):
(-[WKScrollbarPartAnimation setStartValue:]):
(-[WKScrollbarPartAnimation setEndValue:]):
(-[WKScrollbarPartAnimation setCurrentProgress:]):
(-[WKScrollbarPartAnimation invalidate]):
(-[WKScrollerImpDelegate initWithScroller:]):
(-[WKScrollerImpDelegate cancelAnimations]):
(-[WKScrollerImpDelegate scrollerPair]):
(-[WKScrollerImpDelegate convertRectToBacking:]):
(-[WKScrollerImpDelegate convertRectFromBacking:]):
(-[WKScrollerImpDelegate layer]):
(-[WKScrollerImpDelegate mouseLocationInScrollerForScrollerImp:]):
(-[WKScrollerImpDelegate convertRectToLayer:]):
(-[WKScrollerImpDelegate shouldUseLayerPerPartForScrollerImp:]):
(-[WKScrollerImpDelegate effectiveAppearanceForScrollerImp:]):
(-[WKScrollerImpDelegate setUpAlphaAnimation:scrollerPainter:part:animateAlphaTo:duration:]):
(-[WKScrollerImpDelegate scrollerImp:animateKnobAlphaTo:duration:]):
(-[WKScrollerImpDelegate scrollerImp:animateTrackAlphaTo:duration:]):
(-[WKScrollerImpDelegate scrollerImp:animateUIStateTransitionWithDuration:]):
(-[WKScrollerImpDelegate scrollerImp:animateExpansionTransitionWithDuration:]):
(-[WKScrollerImpDelegate scrollerImp:overlayScrollerStateChangedTo:]):
(-[WKScrollerImpDelegate invalidate]):
(WebKit::ScrollerMac::ScrollerMac):
(WebKit::ScrollerMac::~ScrollerMac):
(WebKit::ScrollerMac::attach):
(WebKit::ScrollerMac::setHostLayer):
(WebKit::ScrollerMac::updatePosition):
(WebKit::ScrollerMac::convertFromContent const):
* UIProcess/RemoteLayerTree/mac/ScrollerPairMac.h: Added.
(WebKit::ScrollerPairMac::verticalScroller):
(WebKit::ScrollerPairMac::horizontalScroller):
(WebKit::ScrollerPairMac::scrollerImpPair):
(WebKit::ScrollerPairMac::lastKnownMousePosition const):
* UIProcess/RemoteLayerTree/mac/ScrollerPairMac.mm: Added.

Wraps NSScrollerPairImp and owns the vertical and horizontal scrollers.

(-[WKScrollerImpPairDelegate initWithScrollerPair:]):
(-[WKScrollerImpPairDelegate invalidate]):
(-[WKScrollerImpPairDelegate contentAreaRectForScrollerImpPair:]):
(-[WKScrollerImpPairDelegate inLiveResizeForScrollerImpPair:]):
(-[WKScrollerImpPairDelegate mouseLocationInContentAreaForScrollerImpPair:]):
(-[WKScrollerImpPairDelegate scrollerImpPair:convertContentPoint:toScrollerImp:]):
(-[WKScrollerImpPairDelegate scrollerImpPair:setContentAreaNeedsDisplayInRect:]):
(-[WKScrollerImpPairDelegate scrollerImpPair:updateScrollerStyleForNewRecommendedScrollerStyle:]):
(WebKit::ScrollerPairMac::ScrollerPairMac):
(WebKit::ScrollerPairMac::~ScrollerPairMac):
(WebKit::ScrollerPairMac::handleWheelEvent):
(WebKit::ScrollerPairMac::handleMouseEvent):
(WebKit::ScrollerPairMac::updatePositions):
(WebKit::ScrollerPairMac::contentsSize const):
(WebKit::ScrollerPairMac::visibleContentsRect const):
(WebKit::ScrollerPairMac::useDarkAppearance const):
* UIProcess/RemoteLayerTree/mac/ScrollingTreeFrameScrollingNodeRemoteMac.cpp: Added.

Special node for UI side Mac scrolling. Owns ScrollerPairMac instance.

(WebKit::ScrollingTreeFrameScrollingNodeRemoteMac::ScrollingTreeFrameScrollingNodeRemoteMac):
(WebKit::ScrollingTreeFrameScrollingNodeRemoteMac::~ScrollingTreeFrameScrollingNodeRemoteMac):
(WebKit::ScrollingTreeFrameScrollingNodeRemoteMac::create):
(WebKit::ScrollingTreeFrameScrollingNodeRemoteMac::commitStateBeforeChildren):
(WebKit::ScrollingTreeFrameScrollingNodeRemoteMac::setScrollLayerPosition):
(WebKit::ScrollingTreeFrameScrollingNodeRemoteMac::handleWheelEvent):
(WebKit::ScrollingTreeFrameScrollingNodeRemoteMac::handleMouseEvent):
(WebKit::ScrollingTreeFrameScrollingNodeRemoteMac::scrollingTree const):
* UIProcess/RemoteLayerTree/mac/ScrollingTreeFrameScrollingNodeRemoteMac.h: Added.
* UIProcess/WebPageProxy.cpp:
(WebKit::WebPageProxy::handleMouseEvent):
* WebKit.xcodeproj/project.pbxproj:

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@239689 268f45cc-cd09-0410-ab3c-d52691b4dbfc