Clean compositing inputs for location APIs for sticky-affected elements.

third_party/WebKit/Source/core/dom/Element.cpp

Index: third_party/WebKit/Source/core/dom/Element.cpp
diff --git a/third_party/WebKit/Source/core/dom/Element.cpp b/third_party/WebKit/Source/core/dom/Element.cpp
index 3f31f0a9877d3845d5260312a9899c18ed08faaf..97c267ae2eb0575038c397b8177b0268cb7cc36a 100644
--- a/third_party/WebKit/Source/core/dom/Element.cpp
+++ b/third_party/WebKit/Source/core/dom/Element.cpp
@@ -431,7 +431,7 @@ AtomicString Element::LowercaseIfNecessary(const AtomicString& name) const {
 }
 
 void Element::scrollIntoView(bool align_to_top) {
-  GetDocument().UpdateStyleAndLayoutIgnorePendingStylesheetsForNode(this);
+  EnsureLifecycleValidForLocationAPIs();
 
   if (!GetLayoutObject())
     return;
@@ -456,7 +456,7 @@ void Element::scrollIntoView(bool align_to_top) {
 }
 
 void Element::scrollIntoViewIfNeeded(bool center_if_needed) {
-  GetDocument().UpdateStyleAndLayoutIgnorePendingStylesheetsForNode(this);
+  EnsureLifecycleValidForLocationAPIs();
 
   if (!GetLayoutObject())
     return;
@@ -643,7 +643,7 @@ void Element::CallApplyScroll(ScrollState& scroll_state) {
 }
 
 int Element::OffsetLeft() {
-  GetDocument().UpdateStyleAndLayoutIgnorePendingStylesheetsForNode(this);
+  EnsureLifecycleValidForLocationAPIs();
   if (LayoutBoxModelObject* layout_object = GetLayoutBoxModelObject())
     return AdjustLayoutUnitForAbsoluteZoom(
                LayoutUnit(
@@ -654,7 +654,7 @@ int Element::OffsetLeft() {
 }
 
 int Element::OffsetTop() {
-  GetDocument().UpdateStyleAndLayoutIgnorePendingStylesheetsForNode(this);
+  EnsureLifecycleValidForLocationAPIs();
   if (LayoutBoxModelObject* layout_object = GetLayoutBoxModelObject())
     return AdjustLayoutUnitForAbsoluteZoom(
                LayoutUnit(layout_object->PixelSnappedOffsetTop(OffsetParent())),
@@ -1132,7 +1132,7 @@ IntRect Element::VisibleBoundsInVisualViewport() const {
 }
 
 void Element::ClientQuads(Vector<FloatQuad>& quads) {
-  GetDocument().UpdateStyleAndLayoutIgnorePendingStylesheetsForNode(this);
+  EnsureLifecycleValidForLocationAPIs();
 
   LayoutObject* element_layout_object = GetLayoutObject();
   if (!element_layout_object)
@@ -4328,6 +4328,28 @@ void Element::LogUpdateAttributeIfIsolatedWorldAndInDocument(
   activity_logger->LogEvent("blinkSetAttribute", argv.size(), argv.data());
 }
 
+void Element::EnsureLifecycleValidForLocationAPIs() {
+  if (!InActiveDocument())
+    return;
+
+  GetDocument().UpdateStyleAndLayoutIgnorePendingStylesheets();
+
+  // The location of elements that are position: sticky is not known until
+  // compositing inputs are cleaned. Therefore, for any elements that are either
+  // sticky or are in a sticky sub-tree (e.g. are affected by a sticky element),
+  // we need to also clean compositing inputs.
+  FrameView* view = GetDocument().View();
+  if (UNLIKELY(view && GetLayoutObject() &&
+               GetLayoutObject()->Style()->IsInStickySubtree())) {
+    if (RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
+      // In SPv2, compositing inputs are cleaned as part of PrePaint.
+      view->UpdateAllLifecyclePhasesExceptPaint();
+    } else {
+      view->UpdateLifecycleToCompositingInputsClean();
+    }
+  }
+}
+
 DEFINE_TRACE(Element) {
   if (HasRareData())
     visitor->Trace(GetElementRareData());