Implement incremental paint property tree rebuilding

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

Index: third_party/WebKit/Source/core/layout/LayoutObject.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutObject.h b/third_party/WebKit/Source/core/layout/LayoutObject.h
index c4cf35150e68a740cc9b2c61775d1e1e8db32475..bbff038c681c2ae0a61a5dfb97f7bc6fbf9cf660 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.h
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.h
@@ -1723,6 +1723,11 @@ class CORE_EXPORT LayoutObject : public ImageResourceObserver,
       m_layoutObject.clearPreviousPaintInvalidationRects();
     }
 
+    void setPaintPropertiesInvalid() {
+      m_layoutObject.setPaintPropertiesInvalid();
+    }
+    void setPaintPropertiesValid() { m_layoutObject.setPaintPropertiesValid(); }
+
    protected:
     friend class PaintPropertyTreeBuilder;
     // The following two functions can be called from PaintPropertyTreeBuilder
@@ -1745,6 +1750,21 @@ class CORE_EXPORT LayoutObject : public ImageResourceObserver,
     return MutableForPainting(*this);
   }
 
+  // Paint properties (see: |ObjectPaintProperties|) are built from the Object's
+  // state (location, transform style, etc.) and need to be invalidated when
+  // these values change (see: PaintPropertyTreeBuilder). Invalid paint
+  // properties will be rebuilt during the next document lifecycle update.
+  void setPaintPropertiesInvalid() {
+    m_bitfields.setPaintPropertiesValid(false);
+  }
+  void setPaintPropertiesValid() {
+    DCHECK_EQ(document().lifecycle().state(), DocumentLifecycle::InPrePaint);
+    m_bitfields.setPaintPropertiesValid(true);
+  }
+  bool paintPropertiesValid() const {
+    return m_bitfields.paintPropertiesValid();
+  }
+
   void setIsScrollAnchorObject() { m_bitfields.setIsScrollAnchorObject(true); }
 
   // If unconditionally is true, you are responsible for ensuring that
@@ -2120,12 +2140,13 @@ class CORE_EXPORT LayoutObject : public ImageResourceObserver,
           m_isScrollAnchorObject(false),
           m_scrollAnchorDisablingStyleChanged(false),
           m_hasBoxDecorationBackground(false),
+          m_paintPropertiesValid(false),
           m_positionedState(IsStaticallyPositioned),
           m_selectionState(SelectionNone),
           m_backgroundObscurationState(BackgroundObscurationStatusInvalid),
           m_fullPaintInvalidationReason(PaintInvalidationNone) {}
 
-    // 32 bits have been used in the first word, and 18 in the second.
+    // 32 bits have been used in the first word, and 19 in the second.
 
     // 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
@@ -2286,6 +2307,10 @@ class CORE_EXPORT LayoutObject : public ImageResourceObserver,
     ADD_BOOLEAN_BITFIELD(hasBoxDecorationBackground,
                          HasBoxDecorationBackground);
 
+    // Whether the object paint properties are up to date with the Object's
+    // state (see: setPaintPropertiesInvalid and setPaintPropertiesValid).
+    ADD_BOOLEAN_BITFIELD(paintPropertiesValid, PaintPropertiesValid)
+
    private:
     // This is the cached 'position' value of this object
     // (see ComputedStyle::position).