Round visual rects when crossing frame boundaries.

third_party/WebKit/Source/core/paint/PartPainter.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 "core/paint/PartPainter.h"
 
 #include "core/layout/LayoutPart.h"
 #include "core/paint/BoxPainter.h"
 #include "core/paint/LayoutObjectDrawingRecorder.h"
 #include "core/paint/PaintInfo.h"
@@ skipping 87 matching lines @@
 void PartPainter::paintContents(const PaintInfo& paintInfo, const LayoutPoint& paintOffset)
 {
     LayoutPoint adjustedPaintOffset = paintOffset + m_layoutPart.location();
 
     Widget* widget = m_layoutPart.widget();
     RELEASE_ASSERT(widget);
 
     // Tell the widget to paint now. This is the only time the widget is allowed
     // to paint itself. That way it will composite properly with z-indexed layers.
     IntPoint widgetLocation = widget->frameRect().location();
-    IntPoint paintLocation(roundToInt(adjustedPaintOffset.x() + m_layoutPart.borderLeft() + m_layoutPart.paddingLeft()),
-        roundToInt(adjustedPaintOffset.y() + m_layoutPart.borderTop() + m_layoutPart.paddingTop()));
+    IntPoint paintLocation(roundedIntPoint(adjustedPaintOffset + m_layoutPart.contentBoxOffset()));
 
     IntSize widgetPaintOffset = paintLocation - widgetLocation;
     // When painting widgets into compositing layers, tx and ty are relative to the enclosing compositing layer,
     // not the root. In this case, shift the CTM and adjust the CullRect to be root-relative to fix plugin drawing.
     TransformRecorder transform(paintInfo.context, m_layoutPart,
         AffineTransform::translation(widgetPaintOffset.width(), widgetPaintOffset.height()));
 
     CullRect adjustedCullRect(paintInfo.cullRect(), -widgetPaintOffset);
     widget->paint(paintInfo.context, adjustedCullRect);
 }
 
 } // namespace blink