Change Widget subclasses to use a CullRect instead of an IntRect for painting.

third_party/WebKit/Source/core/paint/ScrollableAreaPainter.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/ScrollableAreaPainter.h"
 
 #include "core/layout/LayoutView.h"
 #include "core/page/Page.h"
 #include "core/paint/LayoutObjectDrawingRecorder.h"
@@ skipping 77 matching lines @@
 void ScrollableAreaPainter::paintOverflowControls(GraphicsContext* context, const IntPoint& paintOffset, const CullRect& cullRect, bool paintingOverlayControls)
 {
     // Don't do anything if we have no overflow.
     if (!scrollableArea().box().hasOverflowClip())
         return;
 
     IntPoint adjustedPaintOffset = paintOffset;
     if (paintingOverlayControls)
         adjustedPaintOffset = scrollableArea().cachedOverlayScrollbarOffset();
 
-    IntRect localDamageRect = cullRect.m_rect;
-    localDamageRect.moveBy(-adjustedPaintOffset);
-
     CullRect adjustedCullRect(cullRect, -adjustedPaintOffset);
 
     // Overlay scrollbars paint in a second pass through the layer tree so that they will paint
     // on top of everything else. If this is the normal painting pass, paintingOverlayControls
     // will be false, and we should just tell the root layer that there are overlay scrollbars
     // that need to be painted. That will cause the second pass through the layer tree to run,
     // and we'll paint the scrollbars then. In the meantime, cache tx and ty so that the
     // second pass doesn't need to re-enter the LayoutTree to get it right.
     if (scrollableArea().hasOverlayScrollbars() && !paintingOverlayControls) {
         scrollableArea().setCachedOverlayScrollbarOffset(paintOffset);
@@ skipping 13 matching lines @@
         return;
     }
 
     // This check is required to avoid painting custom CSS scrollbars twice.
     if (paintingOverlayControls && !scrollableArea().hasOverlayScrollbars())
         return;
 
     {
         if (scrollableArea().horizontalScrollbar() && !scrollableArea().layerForHorizontalScrollbar()) {
             TransformRecorder translateRecorder(*context, *scrollableArea().horizontalScrollbar(), AffineTransform::translation(adjustedPaintOffset.x(), adjustedPaintOffset.y()));
-            scrollableArea().horizontalScrollbar()->paint(context, localDamageRect);
+            scrollableArea().horizontalScrollbar()->paint(context, adjustedCullRect);
         }
         if (scrollableArea().verticalScrollbar() && !scrollableArea().layerForVerticalScrollbar()) {
             TransformRecorder translateRecorder(*context, *scrollableArea().verticalScrollbar(), AffineTransform::translation(adjustedPaintOffset.x(), adjustedPaintOffset.y()));
-            scrollableArea().verticalScrollbar()->paint(context, localDamageRect);
+            scrollableArea().verticalScrollbar()->paint(context, adjustedCullRect);
         }
     }
 
     if (scrollableArea().layerForScrollCorner())
         return;
 
     // We fill our scroll corner with white if we have a scrollbar that doesn't run all the way up to the
     // edge of the box.
     paintScrollCorner(context, adjustedPaintOffset, cullRect);
 
@@ skipping 45 matching lines @@
     LayoutObjectDrawingRecorder recorder(*context, scrollableArea().box(), DisplayItem::ScrollbarCorner, absRect, paintOffset);
     context->fillRect(absRect, Color::white);
 }
 
 PaintLayerScrollableArea& ScrollableAreaPainter::scrollableArea() const
 {
     return *m_scrollableArea;
 }
 
 } // namespace blink