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

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

Index: third_party/WebKit/Source/core/dom/Element.h
diff --git a/third_party/WebKit/Source/core/dom/Element.h b/third_party/WebKit/Source/core/dom/Element.h
index 732a418bc8b010999b9489897b639eb9c439ef16..aa8915fa6a456ee42afbf999ca33854d60a9fd34 100644
--- a/third_party/WebKit/Source/core/dom/Element.h
+++ b/third_party/WebKit/Source/core/dom/Element.h
@@ -847,6 +847,10 @@ class CORE_EXPORT Element : public ContainerNode {
 
   virtual void ParserDidSetAttributes() {}
 
+  // Helper method which ensures that the lifecycle is valid to calculate
+  // location based APIs such as offsetTop.
+  void EnsureLifecycleValidForLocationAPIs();
+
  private:
   void ScrollLayoutBoxBy(const ScrollToOptions&);
   void ScrollLayoutBoxTo(const ScrollToOptions&);