Add a dirty bit for updateDescendantDependentFlags.

Source/core/layout/compositing/DeprecatedPaintLayerCompositor.h

 /*
  * Copyright (C) 2009 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 141 matching lines @@
     GraphicsLayer* layerForHorizontalScrollbar() const { return m_layerForHorizontalScrollbar.get(); }
     GraphicsLayer* layerForVerticalScrollbar() const { return m_layerForVerticalScrollbar.get(); }
     GraphicsLayer* layerForScrollCorner() const { return m_layerForScrollCorner.get(); }
 
     void resetTrackedPaintInvalidationRects();
     void setTracksPaintInvalidations(bool);
 
     virtual String debugName(const GraphicsLayer*) override;
     DocumentLifecycle& lifecycle() const;
 
+    bool needsUpdateDescendantDependentFlags() const { return m_needsUpdateDescendantDependentFlags; }
+    void setNeedsUpdateDescendantDependentFlags() { m_needsUpdateDescendantDependentFlags = true; }
+
     void updatePotentialCompositingReasonsFromStyle(DeprecatedPaintLayer*);
 
     // Whether the layer could ever be composited.
     bool canBeComposited(const DeprecatedPaintLayer*) const;
 
     // FIXME: Move allocateOrClearCompositedDeprecatedPaintLayerMapping to CompositingLayerAssigner once we've fixed
     // the compositing chicken/egg issues.
     bool allocateOrClearCompositedDeprecatedPaintLayerMapping(DeprecatedPaintLayer*, CompositingStateTransitionType compositedLayerUpdate);
 
     void updateDirectCompositingReasons(DeprecatedPaintLayer*);
@@ skipping 51 matching lines @@
     // The root layer doesn't composite if it's a non-scrollable frame.
     // So, after a layout we set this dirty bit to know that we need
     // to recompute whether the root layer should composite even if
     // none of its descendants composite.
     // FIXME: Get rid of all the callers of setCompositingModeEnabled
     // except the one in updateIfNeeded, then rename this to
     // m_compositingDirty.
     bool m_rootShouldAlwaysCompositeDirty;
     bool m_needsUpdateFixedBackground;
     bool m_isTrackingPaintInvalidations; // Used for testing.
+    bool m_inOverlayFullscreenVideo;
+    bool m_needsUpdateDescendantDependentFlags;
 
     RootLayerAttachment m_rootLayerAttachment;
 
     // Enclosing container layer, which clips for iframe content
     OwnPtr<GraphicsLayer> m_containerLayer;
     OwnPtr<GraphicsLayer> m_scrollLayer;
 
     // Enclosing layer for overflow controls and the clipping layer
     OwnPtr<GraphicsLayer> m_overflowControlsHostLayer;
 
     // Layers for overflow controls
     OwnPtr<GraphicsLayer> m_layerForHorizontalScrollbar;
     OwnPtr<GraphicsLayer> m_layerForVerticalScrollbar;
     OwnPtr<GraphicsLayer> m_layerForScrollCorner;
-
-    bool m_inOverlayFullscreenVideo;
 };
 
 } // namespace blink
 
 #endif // DeprecatedPaintLayerCompositor_h