Implement incremental paint property tree rebuilding

third_party/WebKit/Source/core/layout/LayoutObject.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2012 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 1700 matching lines @@
     void setPreviousPositionFromPaintInvalidationBacking(const LayoutPoint& p) {
       m_layoutObject.setPreviousPositionFromPaintInvalidationBacking(p);
     }
     void setPreviousBackgroundObscured(bool b) {
       m_layoutObject.setPreviousBackgroundObscured(b);
     }
     void clearPreviousPaintInvalidationRects() {
       m_layoutObject.clearPreviousPaintInvalidationRects();
     }
 
+    void setNeedsPaintPropertyUpdate() {
+      m_layoutObject.setNeedsPaintPropertyUpdate();
+    }
+    void clearNeedsPaintPropertyUpdate() {
+      m_layoutObject.clearNeedsPaintPropertyUpdate();
+    }
+
    protected:
     friend class PaintPropertyTreeBuilder;
     // The following two functions can be called from PaintPropertyTreeBuilder
     // only.
     ObjectPaintProperties& ensurePaintProperties() {
       return m_layoutObject.ensurePaintProperties();
     }
     ObjectPaintProperties* paintProperties() {
       return const_cast<ObjectPaintProperties*>(
           m_layoutObject.paintProperties());
     }
 
     friend class LayoutObject;
     MutableForPainting(const LayoutObject& layoutObject)
         : m_layoutObject(const_cast<LayoutObject&>(layoutObject)) {}
 
     LayoutObject& m_layoutObject;
   };
   MutableForPainting getMutableForPainting() const {
     return MutableForPainting(*this);
   }
 
+  // Paint properties (see: |ObjectPaintProperties|) are built from an object's
+  // state (location, transform, etc) as well as properties from ancestors.
+  // 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_bitfields.setNeedsPaintPropertyUpdate(true);
+  }
+  void clearNeedsPaintPropertyUpdate() {
+    DCHECK_EQ(document().lifecycle().state(), DocumentLifecycle::InPrePaint);
+    m_bitfields.setNeedsPaintPropertyUpdate(false);
+  }
+  bool needsPaintPropertyUpdate() const {
+    return m_bitfields.needsPaintPropertyUpdate();
+  }
+
   void setIsScrollAnchorObject() { m_bitfields.setIsScrollAnchorObject(true); }
 
   // If unconditionally is true, you are responsible for ensuring that
   // no ScrollAnchors reference this LayoutObject.
   void clearIsScrollAnchorObject(bool unconditionally = false);
 
   bool scrollAnchorDisablingStyleChanged() {
     return m_bitfields.scrollAnchorDisablingStyleChanged();
   }
   void setScrollAnchorDisablingStyleChanged(bool changed) {
@@ skipping 359 matching lines @@
           m_notifiedOfSubtreeChange(false),
           m_consumesSubtreeChangeNotification(false),
           m_childrenInline(false),
           m_containsInlineWithOutlineAndContinuation(false),
           m_alwaysCreateLineBoxesForLayoutInline(false),
           m_previousBackgroundObscured(false),
           m_isBackgroundAttachmentFixedObject(false),
           m_isScrollAnchorObject(false),
           m_scrollAnchorDisablingStyleChanged(false),
           m_hasBoxDecorationBackground(false),
+          m_needsPaintPropertyUpdate(true),
           m_positionedState(IsStaticallyPositioned),
           m_selectionState(SelectionNone),
           m_backgroundObscurationState(BackgroundObscurationStatusInvalid),
           m_fullPaintInvalidationReason(PaintInvalidationNone) {}
 
     // 32 bits have been used in the first word, and 19 in the second.

[Xianzhu, 2016/10/26 19:21:51]

Update the '19' to '20'.

 
     // Self needs layout means that this layout object is marked for a full
     // layout. This is the default layout but it is expensive as it recomputes
     // everything. For CSS boxes, this includes the width (laying out the line
     // boxes again), the margins (due to block collapsing margins), the
     // positions, the height and the potential overflow.
     ADD_BOOLEAN_BITFIELD(selfNeedsLayout, SelfNeedsLayout);
 
     // A positioned movement layout is a specialized type of layout used on
     // positioned objects that only visually moved. This layout is used when
@@ skipping 138 matching lines @@
     // layout should suppress any adjustments that would be made during the next
     // layout by ScrollAnchor objects for which this LayoutObject is on the path
     // from the anchor node to the scroller.
     // See http://bit.ly/sanaclap for more info.
     ADD_BOOLEAN_BITFIELD(scrollAnchorDisablingStyleChanged,
                          ScrollAnchorDisablingStyleChanged);
 
     ADD_BOOLEAN_BITFIELD(hasBoxDecorationBackground,
                          HasBoxDecorationBackground);
 
+    // Whether the paint properties need to be updated. For more details, see
+    // LayoutObject::needsPaintPropertyUpdate().
+    ADD_BOOLEAN_BITFIELD(needsPaintPropertyUpdate, NeedsPaintPropertyUpdate);
+
    private:
     // This is the cached 'position' value of this object
     // (see ComputedStyle::position).
     unsigned m_positionedState : 2;  // PositionedState
     unsigned m_selectionState : 3;   // SelectionState
     // Mutable for getter which lazily update this field.
     mutable unsigned
         m_backgroundObscurationState : 2;        // BackgroundObscurationState
     unsigned m_fullPaintInvalidationReason : 5;  // PaintInvalidationReason
 
@@ skipping 298 matching lines @@
 CORE_EXPORT void showLineTree(const blink::LayoutObject*);
 CORE_EXPORT void showLayoutTree(const blink::LayoutObject* object1);
 // We don't make object2 an optional parameter so that showLayoutTree
 // can be called from gdb easily.
 CORE_EXPORT void showLayoutTree(const blink::LayoutObject* object1,
                                 const blink::LayoutObject* object2);
 
 #endif
 
 #endif  // LayoutObject_h