[css-grid] Use firstInFlowChildBox API for iterate over the grid items

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2006, 2007 Apple Inc. 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 189 matching lines @@
 
   PaintLayerType layerTypeRequired() const override;
 
   bool backgroundIsKnownToBeOpaqueInRect(
       const LayoutRect& localRect) const override;
 
   virtual bool backgroundShouldAlwaysBeClipped() const { return false; }
 
   // Use this with caution! No type checking is done!
   LayoutBox* firstChildBox() const;
+  LayoutBox* firstInFlowChildBox() const;
   LayoutBox* lastChildBox() const;
 
   int pixelSnappedWidth() const { return m_frameRect.pixelSnappedWidth(); }
   int pixelSnappedHeight() const { return m_frameRect.pixelSnappedHeight(); }
 
   void setX(LayoutUnit x) {
     if (x == m_frameRect.x())
       return;
     m_frameRect.setX(x);
     frameRectChanged();
@@ skipping 1348 matching lines @@
   LayoutBox* next = nextSiblingBox();
   while (next && next->isOutOfFlowPositioned())
     next = next->nextSiblingBox();
   return next;
 }
 
 inline LayoutBox* LayoutBox::parentBox() const {
   return toLayoutBox(parent());
 }
 
+inline LayoutBox* LayoutBox::firstInFlowChildBox() const {
+  LayoutBox* first = firstChildBox();
+  while (first && first->isOutOfFlowPositioned())
+    first = first->nextInFlowSiblingBox();

[Manuel Rego, 2016/10/18 20:59:28]

I know I'm late but I think you don't need a loop here.
You could simply change the "while" for an "if",
as you're using nextInFlowSiblingBox().
    

[jfernandez, 2016/10/18 22:25:05]

You are right, indeed. I can do that ASAP in a different
patch.

+  return first;
+}
+
 inline LayoutBox* LayoutBox::firstChildBox() const {
   return toLayoutBox(slowFirstChild());
 }
 
 inline LayoutBox* LayoutBox::lastChildBox() const {
   return toLayoutBox(slowLastChild());
 }
 
 inline LayoutBox* LayoutBox::previousSiblingMultiColumnBox() const {
   ASSERT(isLayoutMultiColumnSpannerPlaceholder() || isLayoutMultiColumnSet());
@@ skipping 25 matching lines @@
 
 inline bool LayoutBox::isForcedFragmentainerBreakValue(EBreak breakValue) {
   return breakValue == BreakColumn || breakValue == BreakLeft ||
          breakValue == BreakPage || breakValue == BreakRecto ||
          breakValue == BreakRight || breakValue == BreakVerso;
 }
 
 }  // namespace blink
 
 #endif  // LayoutBox_h