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

third_party/WebKit/Source/core/paint/PaintLayerScrollableArea.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights
  * reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@gmail.com>
@@ skipping 835 matching lines @@
 
   ClampScrollOffsetAfterOverflowChange();
 
   if (!scrollbars_are_frozen) {
     UpdateScrollableAreaSet(HasScrollableHorizontalOverflow() ||
                             HasScrollableVerticalOverflow());
   }
 
   DisableCompositingQueryAsserts disabler;
   PositionOverflowControls();
+
+  // Layout of a scrollable area, or any of its descendants (sticky or
+  // otherwise), invalidates the cached sticky constraints.
+  InvalidateAllStickyConstraints();

[chrishtr, 2017/04/20 17:40:34]

This looks like an independent bug. Does it deserve its own CL?

[smcgruer, 2017/04/26 14:37:07]

Yes, it probably does. Removed the scroll related stuff, will create a new CL
for it. This means that scrollIntoView/scrollIntoViewIfNeeded will still be
broken after this CL.

 }
 
 void PaintLayerScrollableArea::ClampScrollOffsetAfterOverflowChange() {
   // If a vertical scrollbar was removed, the min/max scroll offsets may have
   // changed, so the scroll offsets needs to be clamped.  If the scroll offset
   // did not change, but the scroll origin *did* change, we still need to notify
   // the scrollbars to update their dimensions.
 
   if (DelayScrollOffsetClampScope::ClampingIsDelayed()) {
     DelayScrollOffsetClampScope::SetNeedsClamp(this);
@@ skipping 1267 matching lines @@
 
 void PaintLayerScrollableArea::DelayScrollOffsetClampScope::
     ClampScrollableAreas() {
   for (auto& scrollable_area : *needs_clamp_)
     scrollable_area->ClampScrollOffsetAfterOverflowChange();
   delete needs_clamp_;
   needs_clamp_ = nullptr;
 }
 
 }  // namespace blink