Migrate WTF::HashSet::add() to ::insert() [part 1 of N]

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 017e0dafe045673093764f7ac01a09e4b1f146a3..34621286a38471106ee33bcd65310ddc9c89db08 100644
--- a/third_party/WebKit/Source/core/layout/LayoutGrid.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutGrid.cpp
@@ -1135,7 +1135,7 @@ double LayoutGrid::computeFlexFactorUnitSize(
       flexFactorSum -= flexFactor;
       if (!additionalTracksToTreatAsInflexible)
         additionalTracksToTreatAsInflexible = WTF::makeUnique<TrackIndexSet>();
-      additionalTracksToTreatAsInflexible->add(index);
+      additionalTracksToTreatAsInflexible->insert(index);
       validFlexFactorUnit = false;
     }
   }
@@ -1532,7 +1532,7 @@ void LayoutGrid::resolveContentBasedTrackSizingFunctions(
                              ? sizingData.columnTracks[trackIndex]
                              : sizingData.rowTracks[trackIndex];
       while (LayoutBox* gridItem = iterator.nextGridItem()) {
-        if (itemsSet.add(gridItem).isNewEntry) {
+        if (itemsSet.insert(gridItem).isNewEntry) {
           const GridSpan& span = grid.gridItemSpan(*gridItem, direction);
           if (span.integerSpan() == 1) {
             resolveContentBasedTrackSizingFunctionsForNonSpanningItems(