Remove ScrollableArea and Scrollbar

sky/engine/core/rendering/RenderBlock.h

Index: sky/engine/core/rendering/RenderBlock.h
diff --git a/sky/engine/core/rendering/RenderBlock.h b/sky/engine/core/rendering/RenderBlock.h
index b777544597d1cd6dc8deb6494f7b0c0f17fce44b..ad2b171b83e5231de947bd14f3799f18b19ac105 100644
--- a/sky/engine/core/rendering/RenderBlock.h
+++ b/sky/engine/core/rendering/RenderBlock.h
@@ -178,8 +178,6 @@ public:
 
     virtual bool nodeAtPoint(const HitTestRequest&, HitTestResult&, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, HitTestAction) override;
 
-    virtual void scrollbarsChanged(bool /*horizontalScrollbarChanged*/, bool /*verticalScrollbarChanged*/) { }
-
     LayoutUnit availableLogicalWidthForContent() const { return max<LayoutUnit>(0, logicalRightOffsetForContent() - logicalLeftOffsetForContent()); }
     LayoutUnit logicalLeftOffsetForContent() const { return borderLeft() + paddingLeft(); }
     LayoutUnit logicalRightOffsetForContent() const { return logicalLeftOffsetForContent() + availableLogicalWidth(); }