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

third_party/WebKit/Source/core/css/resolver/StyleAdjuster.cpp

Index: third_party/WebKit/Source/core/css/resolver/StyleAdjuster.cpp
diff --git a/third_party/WebKit/Source/core/css/resolver/StyleAdjuster.cpp b/third_party/WebKit/Source/core/css/resolver/StyleAdjuster.cpp
index 57ce4f32a3654a19edf93e9414c22d1235eb31e9..850bef6bbebbad114ff3e1974f3cc27d76e729b4 100644
--- a/third_party/WebKit/Source/core/css/resolver/StyleAdjuster.cpp
+++ b/third_party/WebKit/Source/core/css/resolver/StyleAdjuster.cpp
@@ -512,6 +512,15 @@ void StyleAdjuster::AdjustComputedStyle(
       style.ClearMultiCol();
   }
   AdjustStyleForAlignment(style, layout_parent_style);
+
+  // If this node is sticky it marks the creation of a sticky subtree, which we
+  // must track to properly handle document lifecycle in some cases.
+  //
+  // It is possible that this node is already in a sticky subtree (i.e. we have
+  // nested sticky nodes) - in that case the bit will already be set via
+  // inheritance from the ancestor and there is no harm to setting it again.
+  if (style.GetPosition() == EPosition::kSticky)
+    style.SetSubtreeIsSticky(true);
 }
 
 }  // namespace blink