Migrate WTF::HashSet::add() to ::insert() [continued]

third_party/WebKit/Source/platform/scroll/ScrollbarThemeMac.mm

 /*
  * Copyright (C) 2008, 2011 Apple Inc. All Rights Reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 186 matching lines @@
 
 ScrollbarPart ScrollbarThemeMac::invalidateOnThumbPositionChange(
     const ScrollbarThemeClient& scrollbar,
     float oldPosition,
     float newPosition) const {
   // ScrollAnimatorMac will invalidate scrollbar parts if necessary.
   return NoPart;
 }
 
 void ScrollbarThemeMac::registerScrollbar(ScrollbarThemeClient& scrollbar) {
-  scrollbarSet().add(&scrollbar);
+  scrollbarSet().insert(&scrollbar);
 
   bool isHorizontal = scrollbar.orientation() == HorizontalScrollbar;
   RetainPtr<ScrollbarPainter> scrollbarPainter(
       AdoptNS, [[NSClassFromString(@"NSScrollerImp")
                    scrollerImpWithStyle:recommendedScrollerStyle()
                             controlSize:(NSControlSize)scrollbar.controlSize()
                              horizontal:isHorizontal
                    replacingScrollerImp:nil] retain]);
   RetainPtr<BlinkScrollbarObserver> observer(
       AdoptNS,
@@ skipping 191 matching lines @@
 }
 
 // static
 NSScrollerStyle ScrollbarThemeMac::recommendedScrollerStyle() {
   if (RuntimeEnabledFeatures::overlayScrollbarsEnabled())
     return NSScrollerStyleOverlay;
   return gPreferredScrollerStyle;
 }
 
 }  // namespace blink