Title: [224617] trunk/Source/WebCore
- Revision
- 224617
- Author
- simon.fra...@apple.com
- Date
- 2017-11-08 21:27:22 -0800 (Wed, 08 Nov 2017)
Log Message
Cordova: elements with tag position:fixed disappears (flickering) when a long content is scrolling and appears again when the scroll is finished.
https://bugs.webkit.org/show_bug.cgi?id=178066
Reviewed by Tim Horton.
In UIWebView, we were failing to call setIsViewportConstrained() on layers for position:fixed,
causing us to detach their backing store sometimes on page scrolling.
Fix by hoisting the call to RenderLayerBacking::setIsScrollCoordinatedWithViewportConstrainedRole()
up the stack into code that runs for both UIWebView and WKWebView. This required moving some of
the sanity check code up out of updateScrollCoordinatedLayer() into the caller.
Not testable because the bug only manifested in UIWebView.
* rendering/RenderLayerCompositor.cpp:
(WebCore::canCoordinateScrollingForLayer):
(WebCore::RenderLayerCompositor::updateScrollCoordinatedStatus):
(WebCore::RenderLayerCompositor::updateScrollCoordinatedLayer):
Modified Paths
Diff
Modified: trunk/Source/WebCore/ChangeLog (224616 => 224617)
--- trunk/Source/WebCore/ChangeLog 2017-11-09 04:57:38 UTC (rev 224616)
+++ trunk/Source/WebCore/ChangeLog 2017-11-09 05:27:22 UTC (rev 224617)
@@ -1,3 +1,24 @@
+2017-11-08 Simon Fraser <simon.fra...@apple.com>
+
+ Cordova: elements with tag position:fixed disappears (flickering) when a long content is scrolling and appears again when the scroll is finished.
+ https://bugs.webkit.org/show_bug.cgi?id=178066
+
+ Reviewed by Tim Horton.
+
+ In UIWebView, we were failing to call setIsViewportConstrained() on layers for position:fixed,
+ causing us to detach their backing store sometimes on page scrolling.
+
+ Fix by hoisting the call to RenderLayerBacking::setIsScrollCoordinatedWithViewportConstrainedRole()
+ up the stack into code that runs for both UIWebView and WKWebView. This required moving some of
+ the sanity check code up out of updateScrollCoordinatedLayer() into the caller.
+
+ Not testable because the bug only manifested in UIWebView.
+
+ * rendering/RenderLayerCompositor.cpp:
+ (WebCore::canCoordinateScrollingForLayer):
+ (WebCore::RenderLayerCompositor::updateScrollCoordinatedStatus):
+ (WebCore::RenderLayerCompositor::updateScrollCoordinatedLayer):
+
2017-11-08 Zalan Bujtas <za...@apple.com>
[LayoutState cleanup] Move RenderMultiColumnFlow::computeLineGridPaginationOrigin to LayoutState
Modified: trunk/Source/WebCore/rendering/RenderLayerCompositor.cpp (224616 => 224617)
--- trunk/Source/WebCore/rendering/RenderLayerCompositor.cpp 2017-11-09 04:57:38 UTC (rev 224616)
+++ trunk/Source/WebCore/rendering/RenderLayerCompositor.cpp 2017-11-09 05:27:22 UTC (rev 224617)
@@ -3506,6 +3506,11 @@
rootLayer->noteDeviceOrPageScaleFactorChangedIncludingDescendants();
}
+static bool canCoordinateScrollingForLayer(const RenderLayer& layer)
+{
+ return (layer.isRenderViewLayer() || layer.parent()) && layer.isComposited();
+}
+
void RenderLayerCompositor::updateScrollCoordinatedStatus(RenderLayer& layer, OptionSet<ScrollingNodeChangeFlags> changes)
{
LayerScrollCoordinationRoles coordinationRoles = 0;
@@ -3515,7 +3520,10 @@
if (useCoordinatedScrollingForLayer(layer))
coordinationRoles |= Scrolling;
- if (coordinationRoles) {
+ if (layer.isComposited())
+ layer.backing()->setIsScrollCoordinatedWithViewportConstrainedRole(coordinationRoles & ViewportConstrained);
+
+ if (coordinationRoles && canCoordinateScrollingForLayer(layer)) {
if (m_scrollCoordinatedLayers.add(&layer).isNewEntry)
m_subframeScrollLayersNeedReattach = true;
@@ -3721,20 +3729,13 @@
void RenderLayerCompositor::updateScrollCoordinatedLayer(RenderLayer& layer, LayerScrollCoordinationRoles reasons, OptionSet<ScrollingNodeChangeFlags> changes)
{
- auto* scrollingCoordinator = this->scrollingCoordinator();
- if (!scrollingCoordinator || !scrollingCoordinator->coordinatesScrollingForFrameView(m_renderView.frameView()))
- return;
-
bool isRenderViewLayer = layer.isRenderViewLayer();
- if (!layer.parent() && !isRenderViewLayer)
- return;
-
ASSERT(m_scrollCoordinatedLayers.contains(&layer));
ASSERT(layer.isComposited());
- auto* backing = layer.backing();
- if (!backing)
+ auto* scrollingCoordinator = this->scrollingCoordinator();
+ if (!scrollingCoordinator || !scrollingCoordinator->coordinatesScrollingForFrameView(m_renderView.frameView()))
return;
if (!m_renderView.frame().isMainFrame()) {
@@ -3751,6 +3752,8 @@
if (!parentNodeID && !isRenderViewLayer)
return;
+ auto* backing = layer.backing();
+
// Always call this even if the backing is already attached because the parent may have changed.
// If a node plays both roles, fixed/sticky is always the ancestor node of scrolling.
if (reasons & ViewportConstrained) {
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