Invalidate first line display item clients when first line style changes

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 1826 matching lines @@
         style->inheritFrom(*pseudoStyle);
         setStyle(style.release());
         return;
     }
 
     setStyle(pseudoStyle);
 }
 
 void LayoutObject::firstLineStyleDidChange(const ComputedStyle& oldStyle, const ComputedStyle& newStyle)
 {
-    StyleDifference diff = oldStyle.visualInvalidationDiff(newStyle);
-    if (diff.hasDifference()) {
-        // TODO(rune@opera.com): We should use the diff to determine whether a repaint vs. layout
-        // is needed, but for now just assume a layout will be required. The diff code
-        // in LayoutObject::setStyle would need to be factored out so that it could be reused.
-        setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation(LayoutInvalidationReason::StyleChange);
+    StyleDifference diff = adjustStyleDifference(oldStyle.visualInvalidationDiff(newStyle));
+
+    if (diff.needsPaintInvalidation()) {
+        setShouldDoFullPaintInvalidation();
+        if (isLayoutBlockFlow())
+            toLayoutBlockFlow(this)->invalidateDisplayItemClientsOfFirstLine();

[rune, 2015/11/27 09:27:11]

How about FIRST_LINE_INHERITED. firstLineStyleDidChange() will be called on
inline elements on the first line, and necessarily so, even if the ::first-line
style doesn't change. I reported 562418, which I suspect is also a slimming
paint regression. I suspect this CL won't fix that. Could you check?

[Xianzhu, 2015/11/30 18:15:53]

For FIRST_LINE_INHERITED, we'll use the normal paint invalidation on style
change flow: mark the LayoutInline shouldDoFullPaintInvalidation during setStyle
and invalidate all line boxes during paint invalidation
(LayoutInline::invalidateDisplayItemClients()).

crbug.com/562418 seems not a slimming paint regression because it also
reproduces on Safari. It seems a style priority issue or a painting issue. Will
investigate it as a separate issue.

     }
+    if (diff.needsLayout())
+        setNeedsLayoutAndPrefWidthsRecalc(LayoutInvalidationReason::StyleChange);
 }
 
 void LayoutObject::markContainingBlocksForOverflowRecalc()
 {
     for (LayoutBlock* container = containingBlock(); container && !container->childNeedsOverflowRecalcAfterStyleChange(); container = container->containingBlock())
         container->setChildNeedsOverflowRecalcAfterStyleChange();
 }
 
 void LayoutObject::setNeedsOverflowRecalcAfterStyleChange()
 {
@@ skipping 1640 matching lines @@
         const blink::LayoutObject* root = object1;
         while (root->parent())
             root = root->parent();
         root->showLayoutTreeAndMark(object1, "*", object2, "-", 0);
     } else {
         fprintf(stderr, "Cannot showLayoutTree. Root is (nil)\n");
     }
 }
 
 #endif