Generalize visible descendant dirty bits to prepare for more properties.

third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp

Index: third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
diff --git a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
index 219d0f355aac039fbf5846da229643835c6f3ec9..398848c1a1577e5bd6d8f624762f6bfad7f0c1de 100644
--- a/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
+++ b/third_party/WebKit/Source/core/layout/compositing/CompositedLayerMapping.cpp
@@ -1772,10 +1772,17 @@ bool CompositedLayerMapping::updateOverflowControlsLayers(
   }
 
   // If the subtree is invisible, we don't actually need scrollbar layers.
-  bool invisible = m_owningLayer.subtreeIsInvisible();
-  needsHorizontalScrollbarLayer &= !invisible;
-  needsVerticalScrollbarLayer &= !invisible;
-  needsScrollCornerLayer &= !invisible;
+  // Only do this check if at least one of the bits is currently true.
+  // This is important because this method is called during the destructor
+  // of CompositedLayerMapping, which may happen during style recalc,
+  // and therefore visible content status may be invalid.
+  if (needsHorizontalScrollbarLayer || needsVerticalScrollbarLayer ||
+      needsScrollCornerLayer) {
+    bool invisible = m_owningLayer.subtreeIsInvisible();
+    needsHorizontalScrollbarLayer &= !invisible;
+    needsVerticalScrollbarLayer &= !invisible;
+    needsScrollCornerLayer &= !invisible;
+  }
 
   bool horizontalScrollbarLayerChanged = toggleScrollbarLayerIfNeeded(
       m_layerForHorizontalScrollbar, needsHorizontalScrollbarLayer,