Factor painting code from RenderLayerScrollableArea into ScrollableAreaPainter

Source/core/paint/BlockPainter.cpp

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "config.h"
 #include "core/paint/BlockPainter.h"
 
 #include "core/editing/Caret.h"
 #include "core/editing/FrameSelection.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/page/Page.h"
 #include "core/paint/BoxClipper.h"
 #include "core/paint/BoxPainter.h"
 #include "core/paint/InlinePainter.h"
 #include "core/paint/LineBoxListPainter.h"
 #include "core/paint/RenderDrawingRecorder.h"
+#include "core/paint/ScrollableAreaPainter.h"
 #include "core/rendering/GraphicsContextAnnotator.h"
 #include "core/rendering/PaintInfo.h"
 #include "core/rendering/RenderBlock.h"
 #include "core/rendering/RenderFlexibleBox.h"
 #include "core/rendering/RenderInline.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/RenderView.h"
 #include "platform/geometry/LayoutPoint.h"
 #include "platform/geometry/LayoutRect.h"
 #include "platform/graphics/GraphicsContextStateSaver.h"
@@ skipping 52 matching lines @@
     // z-index. We paint after we painted the background/border, so that the scrollbars will
     // sit above the background/border.
     paintOverflowControlsIfNeeded(localPaintInfo, adjustedPaintOffset);
 }
 
 void BlockPainter::paintOverflowControlsIfNeeded(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     PaintPhase phase = paintInfo.phase;
     if (m_renderBlock.hasOverflowClip() && m_renderBlock.style()->visibility() == VISIBLE && (phase == PaintPhaseBlockBackground || phase == PaintPhaseChildBlockBackground) && paintInfo.shouldPaintWithinRoot(&m_renderBlock) && !paintInfo.paintRootBackgroundOnly()) {
         RenderDrawingRecorder recorder(paintInfo.context, &m_renderBlock, paintInfo.phase, pixelSnappedIntRect(paintOffset, m_renderBlock.visualOverflowRect().size()));
-        m_renderBlock.layer()->scrollableArea()->paintOverflowControls(paintInfo.context, roundedIntPoint(paintOffset), paintInfo.rect, false /* paintingOverlayControls */);
+        ScrollableAreaPainter(*m_renderBlock.layer()->scrollableArea()).paintOverflowControls(paintInfo.context, roundedIntPoint(paintOffset), paintInfo.rect, false /* paintingOverlayControls */);
     }
 }
 
 void BlockPainter::paintChildren(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     for (RenderBox* child = m_renderBlock.firstChildBox(); child; child = child->nextSiblingBox())
         paintChild(child, paintInfo, paintOffset);
 }
 
 void BlockPainter::paintChild(RenderBox* child, const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
@@ skipping 383 matching lines @@
         RenderBlock* block = flow->containingBlock();
         for ( ; block && block != &m_renderBlock; block = block->containingBlock())
             accumulatedPaintOffset.moveBy(block->location());
         ASSERT(block);
         InlinePainter(*flow).paintOutline(info, accumulatedPaintOffset);
     }
 }
 
 
 } // namespace blink