Avoid truncation to int when setting background-position coordinates

third_party/WebKit/Source/core/paint/BackgroundImageGeometry.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/BackgroundImageGeometry.h"
 
 #include "core/frame/FrameView.h"
 #include "core/layout/LayoutBox.h"
 #include "core/layout/LayoutBoxModelObject.h"
@@ skipping 284 matching lines @@
         if (fillLayer.size().size.width().isAuto() && backgroundRepeatX != RoundFill) {
             fillTileSize.setWidth(fillTileSize.width() * positioningAreaSize.height() / (nrTiles * fillTileSize.height()));
         }
 
         setTileSize(fillTileSize);
         setPhaseY(tileSize().height() ? tileSize().height() - roundToInt(computedYPosition + top) % tileSize().height() : 0);
         setSpaceSize(IntSize());
     }
 
     if (backgroundRepeatX == RepeatFill) {
-        int xOffset = fillLayer.backgroundXOrigin() == RightEdge ? availableWidth - computedXPosition : computedXPosition;
+        LayoutUnit xOffset = fillLayer.backgroundXOrigin() == RightEdge ? availableWidth - computedXPosition : computedXPosition;
         setPhaseX(tileSize().width() ? tileSize().width() - roundToInt(xOffset + left) % tileSize().width() : 0);
         setSpaceSize(IntSize());
     } else if (backgroundRepeatX == SpaceFill && fillTileSize.width() > 0) {
         int space = getSpaceBetweenImageTiles(positioningAreaSize.width(), tileSize().width());
         int actualWidth = tileSize().width() + space;
 
         if (space >= 0) {
             computedXPosition = roundedMinimumValueForLength(Length(), availableWidth);
             setSpaceSize(IntSize(space, 0));
             setPhaseX(actualWidth ? actualWidth - roundToInt(computedXPosition + left) % actualWidth : 0);
         } else {
             backgroundRepeatX = NoRepeatFill;
         }
     }
     if (backgroundRepeatX == NoRepeatFill) {
-        int xOffset = fillLayer.backgroundXOrigin() == RightEdge ? availableWidth - computedXPosition : computedXPosition;
+        LayoutUnit xOffset = fillLayer.backgroundXOrigin() == RightEdge ? availableWidth - computedXPosition : computedXPosition;
         setNoRepeatX(left + xOffset);
         setSpaceSize(IntSize(0, spaceSize().height()));
     }
 
     if (backgroundRepeatY == RepeatFill) {
-        int yOffset = fillLayer.backgroundYOrigin() == BottomEdge ? availableHeight - computedYPosition : computedYPosition;
+        LayoutUnit yOffset = fillLayer.backgroundYOrigin() == BottomEdge ? availableHeight - computedYPosition : computedYPosition;
         setPhaseY(tileSize().height() ? tileSize().height() - roundToInt(yOffset + top) % tileSize().height() : 0);
         setSpaceSize(IntSize(spaceSize().width(), 0));
     } else if (backgroundRepeatY == SpaceFill && fillTileSize.height() > 0) {
         int space = getSpaceBetweenImageTiles(positioningAreaSize.height(), tileSize().height());
         int actualHeight = tileSize().height() + space;
 
         if (space >= 0) {
             computedYPosition = roundedMinimumValueForLength(Length(), availableHeight);
             setSpaceSize(IntSize(spaceSize().width(), space));
             setPhaseY(actualHeight ? actualHeight - roundToInt(computedYPosition + top) % actualHeight : 0);
         } else {
             backgroundRepeatY = NoRepeatFill;
         }
     }
     if (backgroundRepeatY == NoRepeatFill) {
-        int yOffset = fillLayer.backgroundYOrigin() == BottomEdge ? availableHeight - computedYPosition : computedYPosition;
+        LayoutUnit yOffset = fillLayer.backgroundYOrigin() == BottomEdge ? availableHeight - computedYPosition : computedYPosition;
         setNoRepeatY(top + yOffset);
         setSpaceSize(IntSize(spaceSize().width(), 0));
     }
 
     if (fixedAttachment)
         useFixedAttachment(snappedPaintRect.location());
 
     clip(snappedPaintRect);
 }
 
 } // namespace blink