Replace LayoutObject::skipInvalidationWhenLaidOutChildren() with paintedOutputOfObjectHasNoEffect

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 7a88a69240315972c9088971c8606a36422c663f..215797d439a08306aa53b3e0e77e16d66519e118 100644
--- a/third_party/WebKit/Source/core/layout/LayoutObject.h
+++ b/third_party/WebKit/Source/core/layout/LayoutObject.h
@@ -354,12 +354,6 @@ public:
 
 #endif
 
-    // Correct version of !layoutObjectHasNoBoxEffectObsolete().
-    bool hasBoxEffect() const
-    {
-        return hasBoxDecorationBackground() || style()->hasVisualOverflowingEffect();
-    }

[Xianzhu, 2016/08/03 19:56:36]

This is now directly inlined in the new
LayoutBox::canSkipUnforcedPaintInvalidation().

-
     // LayoutObject tree manipulation
     //////////////////////////////////////////
     virtual bool canHaveChildren() const { return virtualChildren(); }
@@ -444,8 +438,6 @@ private:
     // or from Parent element.
     PassRefPtr<ComputedStyle> getUncachedPseudoStyleFromParentOrShadowHost() const;
 
-    bool skipInvalidationWhenLaidOutChildren() const;
-
 public:
 #ifndef NDEBUG
     void showTreeForThis() const;
@@ -694,8 +686,6 @@ public:
     bool boxDecorationBackgroundIsKnownToBeObscured() const;
     bool hasBackground() const { return style()->hasBackground(); }
 
-    bool needsLayoutBecauseOfChildren() const { return needsLayout() && !selfNeedsLayout() && !needsPositionedMovementLayout() && !needsSimplifiedNormalFlowLayout(); }
-
     bool needsLayout() const
     {
         return m_bitfields.selfNeedsLayout() || m_bitfields.normalChildNeedsLayout() || m_bitfields.posChildNeedsLayout()
@@ -1131,6 +1121,11 @@ public:
     void invalidatePaintIncludingNonSelfPaintingLayerDescendants(const LayoutBoxModelObject& paintInvalidationContainer);
     void setShouldDoFullPaintInvalidationIncludingNonCompositingDescendants();
 
+    // An object needs to check unforced paint invalidation if it's not set shouldDoFullPaintInvalidation,

[chrishtr, 2016/08/03 20:33:51]

Maybe rewrite as:

"unforced paint invalidation is when shouldDoFullPaintInvalidation is false, but
mayNeedPaintInvalidation or childShouldCheckForPaintInvalidation is true. This
returns
true if the object has unforced paint invalidation bits set, but they can be
skipped because its painting geometry will not change for some reason"

[Xianzhu, 2016/08/03 21:30:35]

Done.

+    // but is set mayNeedPaintInvalidation or childShouldCheckForPaintInvalidation. The object can
+    // skip unforced paint invalidation if its painting will not be affected by geometry change.
+    virtual bool canSkipUnforcedPaintInvalidation() const { return false; }
+
     // Returns the rect that should have paint invalidated whenever this object changes. The rect is in the view's
     // coordinate space. This method deals with outlines and overflow.
     virtual LayoutRect absoluteClippedOverflowRect() const;
@@ -1555,7 +1550,7 @@ protected:
 #if ENABLE(ASSERT)
     virtual bool paintInvalidationStateIsDirty() const
     {
-        return m_bitfields.neededLayoutBecauseOfChildren() || shouldCheckForPaintInvalidationRegardlessOfPaintInvalidationState();
+        return shouldCheckForPaintInvalidationRegardlessOfPaintInvalidationState();
     }
 #endif
 
@@ -1748,7 +1743,6 @@ private:
             , m_mayNeedPaintInvalidation(false)
             , m_mayNeedPaintInvalidationSubtree(false)
             , m_shouldInvalidateSelection(false)
-            , m_neededLayoutBecauseOfChildren(false)
             , m_floating(false)
             , m_isAnonymous(!node)
             , m_isText(false)
@@ -1782,7 +1776,7 @@ private:
         {
         }
 
-        // 32 bits have been used in the first word, and 17 in the second.
+        // 32 bits have been used in the first word, and 16 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 everything.
@@ -1833,8 +1827,7 @@ private:
         ADD_BOOLEAN_BITFIELD(childShouldCheckForPaintInvalidation, ChildShouldCheckForPaintInvalidation);
         ADD_BOOLEAN_BITFIELD(mayNeedPaintInvalidation, MayNeedPaintInvalidation);
         ADD_BOOLEAN_BITFIELD(mayNeedPaintInvalidationSubtree, MayNeedPaintInvalidationSubtree);
-        ADD_BOOLEAN_BITFIELD(shouldInvalidateSelection, ShouldInvalidateSelection); // TODO(wangxianzhu): Remove for slimming paint v2.
-        ADD_BOOLEAN_BITFIELD(neededLayoutBecauseOfChildren, NeededLayoutBecauseOfChildren); // TODO(wangxianzhu): Remove for slimming paint v2.
+        ADD_BOOLEAN_BITFIELD(shouldInvalidateSelection, ShouldInvalidateSelection);
 
         // This boolean is the cached value of 'float'
         // (see ComputedStyle::isFloating).
@@ -2051,7 +2044,6 @@ inline void LayoutObject::clearNeedsLayout()
     // Set flags for later stages/cycles.
     setEverHadLayout();
     setMayNeedPaintInvalidation();
-    m_bitfields.setNeededLayoutBecauseOfChildren(needsLayoutBecauseOfChildren());
 
     // Clear needsLayout flags.
     setSelfNeedsLayout(false);