Replace LayoutObject::skipInvalidationWhenLaidOutChildren() with paintedOutputOfObjectHasNoEffect

third_party/WebKit/Source/core/layout/LayoutBox.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 2016 matching lines @@
 {
     ASSERT(isBreakBetweenControllable(previousBreakAfterValue));
     return joinFragmentainerBreakValues(previousBreakAfterValue, breakBefore());
 }
 
 bool LayoutBox::needsForcedBreakBefore(EBreak previousBreakAfterValue) const
 {
     return isForcedFragmentainerBreakValue(classABreakPointValue(previousBreakAfterValue));
 }
 
+bool LayoutBox::canSkipUnforcedPaintInvalidation() const
+{
+    if (getSelectionState() != SelectionNone)

[chrishtr, 2016/08/03 20:33:50]

What's the (brief) explanation for this?

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

Done.

+        return false;
+
+    // In case scrollbars got repositioned (which will typically happen if the layout object got
+    // resized), we cannot skip invalidation.
+    if (hasNonCompositedScrollbars())
+        return false;
+
+    if (hasBoxDecorationBackground() || styleRef().hasVisualOverflowingEffect())

[chrishtr, 2016/08/03 20:33:50]

ditto

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

Done.

+        return false;
+
+    if (hasClipRelatedProperty() || hasControlClip())

[chrishtr, 2016/08/03 20:33:50]

ditto

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

Done.

+        return false;
+
+    return true;
+}
+
 LayoutRect LayoutBox::localOverflowRectForPaintInvalidation() const
 {
     if (style()->visibility() != VISIBLE)
         return LayoutRect();
 
     return selfVisualOverflowRect();
 }
 
 void LayoutBox::inflateVisualRectForReflectionAndFilterUnderContainer(LayoutRect& rect, const LayoutObject& container, const LayoutBoxModelObject* ancestorToStopAt) const
 {
@@ skipping 2918 matching lines @@
         m_rareData->m_snapAreas->remove(&snapArea);
     }
 }
 
 SnapAreaSet* LayoutBox::snapAreas() const
 {
     return m_rareData ? m_rareData->m_snapAreas.get() : nullptr;
 }
 
 } // namespace blink