Clear knownToHaveNoOverflow() for line boxes when recomputing overflow without layout

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

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 3158 matching lines @@
             childrenOverflowChanged = true;
             if (InlineBox* inlineBoxWrapper = toLayoutBlock(layoutObject)->inlineBoxWrapper())
                 lineBoxes.add(&inlineBoxWrapper->root());
         }
     }
 
     // FIXME: Glyph overflow will get lost in this case, but not really a big deal.
     GlyphOverflowAndFallbackFontsMap textBoxDataMap;
     for (ListHashSet<RootInlineBox*>::const_iterator it = lineBoxes.begin(); it != lineBoxes.end(); ++it) {
         RootInlineBox* box = *it;
+        box->clearKnownToHaveNoOverflow();

[Xianzhu, 2016/05/16 22:29:19]

Shouldn't we clearKnownToHaveNoOverflow() in computeOverflow()?

[rhogan, 2016/05/17 17:38:08]

No, because InlineBox::computeOverflow() consults noKnownOverflow().

         box->computeOverflow(box->lineTop(), box->lineBottom(), textBoxDataMap);
     }
     return childrenOverflowChanged;
 }
 
 PositionWithAffinity LayoutBlockFlow::positionForPoint(const LayoutPoint& point)
 {
     if (isAtomicInlineLevel()) {
         PositionWithAffinity position = positionForPointIfOutsideAtomicInlineLevel(point);
         if (!position.isNull())
@@ skipping 135 matching lines @@
             if (!rect.isEmpty())
                 rects.append(rect);
         }
     }
 
     if (inlineElementContinuation)
         inlineElementContinuation->addOutlineRects(rects, additionalOffset + (inlineElementContinuation->containingBlock()->location() - location()), includeBlockOverflows);
 }
 
 } // namespace blink