Fixed elements should not rubber-band in WK2, nor remain at negative offsets
https://bugs.webkit.org/show_bug.cgi?id=167484
rdar://problem/29453068
Reviewed by Dean Jackson.
Source/WebCore:
There were various problems with the layout rect computation:
1. It ignored the scrollBehaviorForFixedElements() which we use to avoid rubber-banding fixed
elements in WK2, but allow in WK1, so make use of that.
2. Sometimes layouts/paints of fixed elements would be triggered when coalesced calls to
AsyncScrollingCoordinator::scheduleUpdateScrollPositionAfterAsyncScroll() failed to
copy the layoutViewportOrigin to the scheduled update.
3. The layout viewport could be left with a negative top/left after rubber-banding.
Also add a way to do unconstrained scrollTo(), so that a test can call window.scrollTo(-10, -10) to
simulate rubberbanding.
Tests: fast/visual-viewport/rubberbanding-viewport-rects-header-footer.html
fast/visual-viewport/rubberbanding-viewport-rects.html
* page/FrameView.cpp:
(WebCore::FrameView::computeLayoutViewportOrigin): Handle ScrollBehaviorForFixedElements, incorporating it
into logic that clamps layoutViewportOrigin between min/max when rubberbanding is not allowed, or not in progress.
(WebCore::FrameView::updateLayoutViewport): Pass in scrollBehaviorForFixedElements().
(WebCore::FrameView::visibleDocumentRect): The clamping here was preventing the visible rect from
escaping the document bounds, which caused fixed elements to bounce with rubber-banding, so remove the clamping,
and fix the logic to allow rubber-banding while taking headers and footers into account.
* page/FrameView.h:
* page/scrolling/AsyncScrollingCoordinator.cpp:
(WebCore::AsyncScrollingCoordinator::scheduleUpdateScrollPositionAfterAsyncScroll): layoutViewportOrigin has to
be pushed onto the scheduled update, just like scroll position.
* page/scrolling/ScrollingTreeFrameScrollingNode.cpp:
(WebCore::ScrollingTreeFrameScrollingNode::layoutViewportForScrollPosition): Pass in m_behaviorForFixed.
* platform/ScrollView.cpp:
(WebCore::ScrollView::ScrollView):
(WebCore::ScrollView::adjustScrollPositionWithinRange):
(WebCore::ScrollView::setScrollOffset):
* platform/ScrollView.h:
(WebCore::ScrollView::setAllowsUnclampedScrollPositionForTesting):
(WebCore::ScrollView::allowsUnclampedScrollPosition):
* testing/InternalSettings.cpp:
(WebCore::InternalSettings::setAllowUnclampedScrollPosition):
* testing/InternalSettings.h:
* testing/InternalSettings.idl:
Source/WebKit2:
Pass in StickToViewportBounds as we did before visual viewports.
* UIProcess/ios/WebPageProxyIOS.mm:
(WebKit::WebPageProxy::computeCustomFixedPositionRect):
LayoutTests:
Add two tests that use internals.settings.setAllowUnclampedScrollPosition(true) and then
over-scroll to simulator rubber-banding, dumping viewport rects.
setAllowUnclampedScrollPosition() only works in WebKit2, so skip the tests elsewhere.
* TestExpectations:
* fast/visual-viewport/rubberbanding-viewport-rects-expected.txt: Added.
* fast/visual-viewport/rubberbanding-viewport-rects-header-footer-expected.txt: Added.
* fast/visual-viewport/rubberbanding-viewport-rects-header-footer.html: Added.
* fast/visual-viewport/rubberbanding-viewport-rects.html: Added.
* platform/ios-simulator-wk2/TestExpectations:
* platform/ios-simulator-wk2/fast/visual-viewport/rubberbanding-viewport-rects-expected.txt: Added.
* platform/ios-simulator-wk2/fast/visual-viewport/rubberbanding-viewport-rects-header-footer-expected.txt: Added.
* platform/mac-wk2/TestExpectations:
git-svn-id: http://svn.webkit.org/repository/webkit/trunk@211379 268f45cc-cd09-0410-ab3c-d52691b4dbfc
diff --git a/LayoutTests/TestExpectations b/LayoutTests/TestExpectations
index bb2b6c1..7bb6513 100644
--- a/LayoutTests/TestExpectations
+++ b/LayoutTests/TestExpectations
@@ -89,6 +89,10 @@
# ApplePay is only available on iOS (greater than iOS 10) and macOS (greater than macOS 10.12) and only for WebKit2.
http/tests/ssl/applepay/ [ Skip ]
+# Only WK2 allows unconstrained scrolling
+fast/visual-viewport/rubberbanding-viewport-rects.html [ Skip ]
+fast/visual-viewport/rubberbanding-viewport-rects-header-footer.html [ Skip ]
+
#//////////////////////////////////////////////////////////////////////////////////////////
# End platform-specific tests.
#//////////////////////////////////////////////////////////////////////////////////////////
