[CSS Grid Layout] Add support to place items using named grid lines

Source/core/css/resolver/StyleBuilderConverter.cpp

Index: Source/core/css/resolver/StyleBuilderConverter.cpp
diff --git a/Source/core/css/resolver/StyleBuilderConverter.cpp b/Source/core/css/resolver/StyleBuilderConverter.cpp
index 78cf2176280d254986e75953dfbcca8ed67df1a3..392aefac446052c16a5052f9ca37fb2557b25c64 100644
--- a/Source/core/css/resolver/StyleBuilderConverter.cpp
+++ b/Source/core/css/resolver/StyleBuilderConverter.cpp
@@ -104,7 +104,6 @@ EGlyphOrientation StyleBuilderConverter::convertGlyphOrientation(StyleResolverSt
     return GO_270DEG;
 }
 
-
 GridPosition StyleBuilderConverter::convertGridPosition(StyleResolverState&, CSSValue* value)
 {
     // We accept the specification's grammar:
@@ -210,6 +209,24 @@ bool StyleBuilderConverter::convertGridTrackList(CSSValue* value, Vector<GridTra
     return true;
 }
 
+void StyleBuilderConverter::createImplicitNamedGridLinesFromGridArea(const NamedGridAreaMap& namedGridAreas, NamedGridLinesMap& namedGridLines, GridTrackSizingDirection direction)
+{
+    NamedGridAreaMap::const_iterator end = namedGridAreas.end();
+    for (NamedGridAreaMap::const_iterator it = namedGridAreas.begin(); it != end; ++it) {
+        GridSpan areaSpan = direction == ForRows ? it->value.rows : it->value.columns;
+        {
+            NamedGridLinesMap::AddResult startResult = namedGridLines.add(it->key + "-start", Vector<size_t>());
+            startResult.storedValue->value.append(areaSpan.resolvedInitialPosition.toInt());
+            std::sort(startResult.storedValue->value.begin(), startResult.storedValue->value.end());
+        }
+        {
+            NamedGridLinesMap::AddResult endResult = namedGridLines.add(it->key + "-end", Vector<size_t>());
+            endResult.storedValue->value.append(areaSpan.resolvedFinalPosition.toInt() + 1);
+            std::sort(endResult.storedValue->value.begin(), endResult.storedValue->value.end());
+        }
+    }
+}
+
 Length StyleBuilderConverter::convertLength(StyleResolverState& state, CSSValue* value)
 {
     CSSPrimitiveValue* primitiveValue = toCSSPrimitiveValue(value);