Replace coversExtraPixels with simpler logic

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
@@ skipping 2222 matching lines @@
   // floats and out-of-flow positioned objects may be affected by a break-after
   // value of the previous in-flow object, even though we're not at a class A
   // break point.
   EBreak breakValue = isFloatingOrOutOfFlowPositioned()
                           ? previousBreakAfterValue
                           : classABreakPointValue(previousBreakAfterValue);
   return isForcedFragmentainerBreakValue(breakValue);
 }
 
 bool LayoutBox::paintedOutputOfObjectHasNoEffectRegardlessOfSize() const {
-  // In case scrollbars got repositioned (which will typically happen if the box
-  // got resized), we cannot skip invalidation.
-  if (hasNonCompositedScrollbars())
+  if (hasNonCompositedScrollbars() || getSelectionState() != SelectionNone ||
+      hasBoxDecorationBackground() || styleRef().hasBoxDecorations() ||
+      styleRef().hasVisualOverflowingEffect())
     return false;
 
-  // Cannot skip paint invalidation if the box has real things to paint.
-  if (getSelectionState() != SelectionNone || hasBoxDecorationBackground() ||
-      styleRef().hasBoxDecorations() || styleRef().hasVisualOverflowingEffect())
-    return false;
-
-  // If the box has clip, we need issue a paint invalidation to cover the
-  // changed part of children because of change of clip when the box got
-  // resized. In theory the children should invalidate themselves when ancestor
-  // clip changes, but for now this is missing and ensuring it may hurt
-  // performance.
-  // TODO(wangxianzhu): Paint invalidation for clip change will be different in
-  //                    spv2.
-  if (hasClipRelatedProperty() || hasControlClip())
-    return false;
+  // If the box has clip or mask, we need issue paint invalidation to cover
+  // the changed part of children when the box got resized. In SPv2 this is
+  // handled by detecting paint property changes.
+  if (!RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
+    if (hasClipRelatedProperty() || hasControlClip() || hasMask())
+      return false;
+  }
 
   return true;
 }
 
 LayoutRect LayoutBox::localOverflowRectForPaintInvalidation() const {
   if (style()->visibility() != EVisibility::Visible)
     return LayoutRect();
 
   return selfVisualOverflowRect();
 }
@@ skipping 3323 matching lines @@
   LayoutRect rect = frameRect();
 
   LayoutBlock* block = containingBlock();
   if (block)
     block->adjustChildDebugRect(rect);
 
   return rect;
 }
 
 }  // namespace blink