Establish a list marker's offset before floats have been added to its line

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2006 Andrew Wellington (proton@wiretapped.net)
  * Copyright (C) 2010 Daniel Bates (dbates@intudata.com)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 25 matching lines @@
 namespace blink {
 
 const int cMarkerPaddingPx = 7;
 
 // TODO(glebl): Move to WebKit/Source/core/css/html.css after
 // Blink starts to support ::marker crbug.com/457718
 // Recommended UA margin for list markers.
 const int cUAMarkerMarginEm = 1;
 
 LayoutListMarker::LayoutListMarker(LayoutListItem* item)
-    : LayoutBox(nullptr), m_listItem(item) {
+    : LayoutBox(nullptr), m_listItem(item), m_lineOffset() {
   setInline(true);
   setIsAtomicInlineLevel(true);
 }
 
 LayoutListMarker::~LayoutListMarker() {}
 
 void LayoutListMarker::willBeDestroyed() {
   if (m_image)
     m_image->removeClient(this);
   LayoutBox::willBeDestroyed();
@@ skipping 75 matching lines @@
 
 void LayoutListMarker::paint(const PaintInfo& paintInfo,
                              const LayoutPoint& paintOffset) const {
   ListMarkerPainter(*this).paint(paintInfo, paintOffset);
 }
 
 void LayoutListMarker::layout() {
   ASSERT(needsLayout());
   LayoutAnalyzer::Scope analyzer(*this);
 
+  LayoutUnit blockOffset;
+  for (LayoutBox* o = parentBox(); o != listItem(); o = o->parentBox()) {

[eae, 2016/12/07 21:30:45]

Is parentBox guaranteed to be non-null? If not we might want to change the
condition to:

o && o != listItem()

+    blockOffset += o->logicalTop();
+  }
+  if (listItem()->style()->isLeftToRightDirection()) {
+    m_lineOffset = listItem()->logicalLeftOffsetForLine(
+        blockOffset, DoNotIndentText, LayoutUnit());
+  } else {
+    m_lineOffset = listItem()->logicalRightOffsetForLine(
+        blockOffset, DoNotIndentText, LayoutUnit());
+  }
   if (isImage()) {
     updateMarginsAndContent();
     LayoutSize imageSize(imageBulletSize());
     setWidth(imageSize.width());
     setHeight(imageSize.height());
   } else {
     const SimpleFontData* fontData = style()->font().primaryFont();
     DCHECK(fontData);
     setLogicalWidth(minPreferredLogicalWidth());
     setLogicalHeight(
@@ skipping 334 matching lines @@
   if (style()) {
     // Reuse the current margins. Otherwise resetting the margins to initial
     // values would trigger unnecessary layout.
     newStyle->setMarginStart(style()->marginStart());
     newStyle->setMarginEnd(style()->marginRight());
   }
   setStyle(newStyle.release());
 }
 
 }  // namespace blink