Use refs for non-null GraphicsContext, Scrollbar, etc. in scrollbar related code

third_party/WebKit/Source/core/layout/compositing/PaintLayerCompositor.cpp

 /*
  * Copyright (C) 2009, 2010 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 786 matching lines @@
 
     // Frame scrollbars are painted in the space of the containing frame, not the local space of the scrollbar.
     const IntPoint& paintOffset = scrollbar->frameRect().location();
     IntRect transformedClip = clip;
     transformedClip.moveBy(paintOffset);
 
     AffineTransform translation;
     translation.translate(-paintOffset.x(), -paintOffset.y());
     TransformRecorder transformRecorder(context, *scrollbar, translation);
 
-    scrollbar->paint(&context, CullRect(transformedClip));
+    scrollbar->paint(context, CullRect(transformedClip));
 }
 
 IntRect PaintLayerCompositor::computeInterestRect(const GraphicsLayer* graphicsLayer, const IntRect&) const
 {
     return enclosingIntRect(FloatRect(FloatPoint(), graphicsLayer->size()));
 }
 
 void PaintLayerCompositor::paintContents(const GraphicsLayer* graphicsLayer, GraphicsContext& context, GraphicsLayerPaintingPhase, const IntRect& interestRect) const
 {
     if (graphicsLayer == layerForHorizontalScrollbar())
         paintScrollbar(m_layoutView.frameView()->horizontalScrollbar(), context, interestRect);
     else if (graphicsLayer == layerForVerticalScrollbar())
         paintScrollbar(m_layoutView.frameView()->verticalScrollbar(), context, interestRect);
     else if (graphicsLayer == layerForScrollCorner())
-        FramePainter(*m_layoutView.frameView()).paintScrollCorner(&context, interestRect);
+        FramePainter(*m_layoutView.frameView()).paintScrollCorner(context, interestRect);
 }
 
 bool PaintLayerCompositor::supportsFixedRootBackgroundCompositing() const
 {
     if (Settings* settings = m_layoutView.document().settings())
         return settings->preferCompositingToLCDTextEnabled();
     return false;
 }
 
 bool PaintLayerCompositor::needsFixedRootBackgroundLayer(const PaintLayer* layer) const
@@ skipping 204 matching lines @@
     if (!m_rootContentLayer)
         return;
 
     detachRootLayer();
 
     if (m_layerForHorizontalScrollbar) {
         m_layerForHorizontalScrollbar->removeFromParent();
         m_layerForHorizontalScrollbar = nullptr;
         if (ScrollingCoordinator* scrollingCoordinator = this->scrollingCoordinator())
             scrollingCoordinator->scrollableAreaScrollbarLayerDidChange(m_layoutView.frameView(), HorizontalScrollbar);
-        if (Scrollbar* horizontalScrollbar = m_layoutView.frameView()->horizontalScrollbar())
-            m_layoutView.frameView()->setScrollbarNeedsPaintInvalidation(horizontalScrollbar);
+        m_layoutView.frameView()->setScrollbarNeedsPaintInvalidation(HorizontalScrollbar);
     }
 
     if (m_layerForVerticalScrollbar) {
         m_layerForVerticalScrollbar->removeFromParent();
         m_layerForVerticalScrollbar = nullptr;
         if (ScrollingCoordinator* scrollingCoordinator = this->scrollingCoordinator())
             scrollingCoordinator->scrollableAreaScrollbarLayerDidChange(m_layoutView.frameView(), VerticalScrollbar);
-        if (Scrollbar* verticalScrollbar = m_layoutView.frameView()->verticalScrollbar())
-            m_layoutView.frameView()->setScrollbarNeedsPaintInvalidation(verticalScrollbar);
+        m_layoutView.frameView()->setScrollbarNeedsPaintInvalidation(VerticalScrollbar);
     }
 
     if (m_layerForScrollCorner) {
         m_layerForScrollCorner = nullptr;
         m_layoutView.frameView()->setScrollCornerNeedsPaintInvalidation();
     }
 
     if (m_overflowControlsHostLayer) {
         m_overflowControlsHostLayer = nullptr;
         m_containerLayer = nullptr;
@@ skipping 138 matching lines @@
     } else if (graphicsLayer == m_scrollLayer.get()) {
         name = "Frame Scrolling Layer";
     } else {
         ASSERT_NOT_REACHED();
     }
 
     return name;
 }
 
 } // namespace blink