Remove Scrollbar dependency on AXObjectCache

Source/core/platform/ScrollableArea.cpp

Index: Source/core/platform/ScrollableArea.cpp
diff --git a/Source/core/platform/ScrollableArea.cpp b/Source/core/platform/ScrollableArea.cpp
index 0c608acb7f7fd22c5b7b8b13c88c1b23837ca529..3fa7616400dab9c67f60be057ab1873b29297086 100644
--- a/Source/core/platform/ScrollableArea.cpp
+++ b/Source/core/platform/ScrollableArea.cpp
@@ -275,30 +275,23 @@ void ScrollableArea::finishCurrentScrollAnimations() const
         scrollAnimator->finishCurrentScrollAnimations();
 }
 
-void ScrollableArea::didAddVerticalScrollbar(Scrollbar* scrollbar)
+void ScrollableArea::didAddScrollbar(Scrollbar* scrollbar, ScrollbarOrientation orientation)
 {
-    scrollAnimator()->didAddVerticalScrollbar(scrollbar);
-
-    // <rdar://problem/9797253> AppKit resets the scrollbar's style when you attach a scrollbar
-    setScrollbarOverlayStyle(scrollbarOverlayStyle());
-}
-
-void ScrollableArea::willRemoveVerticalScrollbar(Scrollbar* scrollbar)
-{
-    scrollAnimator()->willRemoveVerticalScrollbar(scrollbar);
-}
-
-void ScrollableArea::didAddHorizontalScrollbar(Scrollbar* scrollbar)
-{
-    scrollAnimator()->didAddHorizontalScrollbar(scrollbar);
+    if (orientation == VerticalScrollbar)
+        scrollAnimator()->didAddVerticalScrollbar(scrollbar);
+    else
+        scrollAnimator()->didAddHorizontalScrollbar(scrollbar);
 
     // <rdar://problem/9797253> AppKit resets the scrollbar's style when you attach a scrollbar
     setScrollbarOverlayStyle(scrollbarOverlayStyle());
 }
 
-void ScrollableArea::willRemoveHorizontalScrollbar(Scrollbar* scrollbar)
+void ScrollableArea::willRemoveScrollbar(Scrollbar* scrollbar, ScrollbarOrientation orientation)
 {
-    scrollAnimator()->willRemoveHorizontalScrollbar(scrollbar);
+    if (orientation == VerticalScrollbar)
+        scrollAnimator()->willRemoveVerticalScrollbar(scrollbar);
+    else
+        scrollAnimator()->willRemoveHorizontalScrollbar(scrollbar);
 }
 
 void ScrollableArea::contentsResized()