Early-out from the prepaint tree walk

third_party/WebKit/Source/core/frame/FrameView.h

 /*
    Copyright (C) 1997 Martin Jones (mjones@kde.org)
              (C) 1998 Waldo Bastian (bastian@kde.org)
              (C) 1998, 1999 Torben Weis (weis@kde.org)
              (C) 1999 Lars Knoll (knoll@kde.org)
              (C) 1999 Antti Koivisto (koivisto@kde.org)
    Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights
    reserved.
 
    This library is free software; you can redistribute it and/or
@@ skipping 710 matching lines @@
       std::unique_ptr<PropertyTreeState> state) {
     m_totalPropertyTreeStateForContents = std::move(state);
   }
   const PropertyTreeState* totalPropertyTreeStateForContents() const {
     return m_totalPropertyTreeStateForContents.get();
   }
 
   // Paint properties (e.g., m_preTranslation, etc.) are built from the
   // FrameView's state (e.g., x(), y(), etc.) as well as inherited context.
   // When these inputs change, setNeedsPaintPropertyUpdate will cause a property
-  // tree update during the next document lifecycle update.
-  // TODO(pdr): Add additional granularity such as the ability to signal that
-  // only a local paint property update is needed.
-  void setNeedsPaintPropertyUpdate() { m_needsPaintPropertyUpdate = true; }
+  // tree update during the next document lifecycle update. For subframes,
+  // the owning LayoutObject is marked as having a descendant needing an update.
+  void setNeedsPaintPropertyUpdate();
+  // Same as |setNeedsPaintPropertyUpdate| but does not notify the owning
+  // LayoutObject as having a descendant needing a paint property update.
+  void setNeedsPaintPropertyUpdateWithoutMarkingAncestors() {
+    DCHECK_EQ(lifecycle().state(), DocumentLifecycle::InPrePaint);
+    m_needsPaintPropertyUpdate = true;
+  }
   void clearNeedsPaintPropertyUpdate() {
     DCHECK_EQ(lifecycle().state(), DocumentLifecycle::InPrePaint);
     m_needsPaintPropertyUpdate = false;
   }
   bool needsPaintPropertyUpdate() const { return m_needsPaintPropertyUpdate; }
   // TODO(ojan): Merge this with IntersectionObserver once it lands.
   IntRect computeVisibleArea();
 
   // Viewport size that should be used for viewport units (i.e. 'vh'/'vw').
   FloatSize viewportSizeForViewportUnits() const;
@@ skipping 407 matching lines @@
                   widget.isFrameView());
 DEFINE_TYPE_CASTS(FrameView,
                   ScrollableArea,
                   scrollableArea,
                   scrollableArea->isFrameView(),
                   scrollableArea.isFrameView());
 
 }  // namespace blink
 
 #endif  // FrameView_h