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

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

Index: third_party/WebKit/Source/core/layout/LayoutGrid.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutGrid.cpp b/third_party/WebKit/Source/core/layout/LayoutGrid.cpp
index 438d518648bf5d113cde2b62a4ba90cc3751a2e3..001bfe8d48d6a656c9e05451807fe278d08ca305 100644
--- a/third_party/WebKit/Source/core/layout/LayoutGrid.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutGrid.cpp
@@ -492,9 +492,9 @@ void LayoutGrid::layoutBlock(bool relayoutChildren) {
     // computed again in the updateLogicalWidth call bellow.
     if (sizesLogicalWidthToFitContent(styleRef().logicalWidth()) ||
         styleRef().logicalWidth().isIntrinsicOrAuto()) {
-      for (auto* child = firstChildBox(); child;
+      for (auto* child = firstInFlowChildBox(); child;
            child = child->nextInFlowSiblingBox()) {
-        if (child->isOutOfFlowPositioned() || !isOrthogonalChild(*child))
+        if (!isOrthogonalChild(*child))
           continue;
         child->clearOverrideSize();
         child->clearContainingBlockOverrideSize();
@@ -1995,11 +1995,8 @@ void LayoutGrid::populateExplicitGridAndOrderIterator() {
 
   ASSERT(m_gridItemsIndexesMap.isEmpty());
   size_t childIndex = 0;
-  for (LayoutBox* child = firstChildBox(); child;
+  for (LayoutBox* child = firstInFlowChildBox(); child;
        child = child->nextInFlowSiblingBox()) {
-    if (child->isOutOfFlowPositioned())
-      continue;
-
     populator.collectChild(child);
     m_gridItemsIndexesMap.set(child, childIndex++);