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

Source/core/css/resolver/StyleBuilderCustom.cpp

Index: Source/core/css/resolver/StyleBuilderCustom.cpp
diff --git a/Source/core/css/resolver/StyleBuilderCustom.cpp b/Source/core/css/resolver/StyleBuilderCustom.cpp
index d859c5ef4b42b8ecc27482eac5f08725642f02ec..a70e7be3d856b20d92b6d55aee21780e5d93809c 100644
--- a/Source/core/css/resolver/StyleBuilderCustom.cpp
+++ b/Source/core/css/resolver/StyleBuilderCustom.cpp
@@ -1049,6 +1049,22 @@ if (isInitial) { \
     return; \
 }
 
+static void 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());
+    }
+}
+
 static GridLength createGridTrackBreadth(CSSPrimitiveValue* primitiveValue, const StyleResolverState& state)
 {
     if (primitiveValue->getValueID() == CSSValueMinContent)
@@ -1738,6 +1754,11 @@ void StyleBuilder::oldApplyProperty(CSSPropertyID id, StyleResolverState& state,
         OrderedNamedGridLines orderedNamedGridLines;
         if (!createGridTrackList(value, trackSizes, namedGridLines, orderedNamedGridLines, state))
             return;
+
+        const NamedGridAreaMap& namedGridAreas = state.style()->namedGridArea();
+        if (!namedGridAreas.isEmpty())
+            createImplicitNamedGridLinesFromGridArea(namedGridAreas, namedGridLines, ForColumns);
+
         state.style()->setGridTemplateColumns(trackSizes);
         state.style()->setNamedGridColumnLines(namedGridLines);
         state.style()->setOrderedNamedGridColumnLines(orderedNamedGridLines);
@@ -1762,6 +1783,11 @@ void StyleBuilder::oldApplyProperty(CSSPropertyID id, StyleResolverState& state,
         OrderedNamedGridLines orderedNamedGridLines;
         if (!createGridTrackList(value, trackSizes, namedGridLines, orderedNamedGridLines, state))
             return;
+
+        const NamedGridAreaMap& namedGridAreas = state.style()->namedGridArea();
+        if (!namedGridAreas.isEmpty())
+            createImplicitNamedGridLinesFromGridArea(namedGridAreas, namedGridLines, ForRows);
+
         state.style()->setGridTemplateRows(trackSizes);
         state.style()->setNamedGridRowLines(namedGridLines);
         state.style()->setOrderedNamedGridRowLines(orderedNamedGridLines);
@@ -1822,7 +1848,16 @@ void StyleBuilder::oldApplyProperty(CSSPropertyID id, StyleResolverState& state,
         }
 
         CSSGridTemplateAreasValue* gridTemplateAreasValue = toCSSGridTemplateAreasValue(value);
-        state.style()->setNamedGridArea(gridTemplateAreasValue->gridAreaMap());
+        const NamedGridAreaMap& newNamedGridAreas = gridTemplateAreasValue->gridAreaMap();
+
+        NamedGridLinesMap namedGridColumnLines = state.style()->namedGridColumnLines();
+        NamedGridLinesMap namedGridRowLines = state.style()->namedGridRowLines();

[Julien - ping for review, 2014/05/12 11:42:12]

You're right about RenderStyle returning a constant reference, we could expose a
mutableNamedGridColumnLines() or just do the copy.

I have a slight preference for the latter as it's more efficient and compact but
I won't push either way.

+        createImplicitNamedGridLinesFromGridArea(newNamedGridAreas, namedGridColumnLines, ForColumns);
+        createImplicitNamedGridLinesFromGridArea(newNamedGridAreas, namedGridRowLines, ForRows);
+        state.style()->setNamedGridColumnLines(namedGridColumnLines);
+        state.style()->setNamedGridRowLines(namedGridRowLines);
+
+        state.style()->setNamedGridArea(newNamedGridAreas);
         state.style()->setNamedGridAreaRowCount(gridTemplateAreasValue->rowCount());
         state.style()->setNamedGridAreaColumnCount(gridTemplateAreasValue->columnCount());
         return;