Force compositing inputs to be clean for getBoundingClientRect

third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp

Index: third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp b/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp
index 486a11a43eb50a95648e8c40706d57d7d6d7f796..60dd69c56611df08e64fbab84c577e38d05a9cee 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp
@@ -104,7 +104,7 @@ bool LayoutBoxModelObject::hasAcceleratedCompositing() const {
 }
 
 LayoutBoxModelObject::LayoutBoxModelObject(ContainerNode* node)
-    : LayoutObject(node) {}
+    : LayoutObject(node), m_isInStickySubtree(false) {}
 
 bool LayoutBoxModelObject::usesCompositedScrolling() const {
   return hasOverflowClip() && hasLayer() &&
@@ -421,6 +421,11 @@ void LayoutBoxModelObject::styleDidChange(StyleDifference diff,
         frameView->removeViewportConstrainedObject(this);
     }
   }
+
+  m_isInStickySubtree =
+      style()->position() == StickyPosition ||
+      (parent() && parent()->enclosingBoxModelObject() &&
+       parent()->enclosingBoxModelObject()->isInStickySubtree());
 }
 
 void LayoutBoxModelObject::invalidateStickyConstraints() {