Round off error while calculating the background-size: contain/cover.

Source/core/rendering/RenderBoxModelObject.cpp

Index: Source/core/rendering/RenderBoxModelObject.cpp
diff --git a/Source/core/rendering/RenderBoxModelObject.cpp b/Source/core/rendering/RenderBoxModelObject.cpp
index f978c7a4ffd12272bd05d5d0e7921ffc3b84b580..415f526aea75777c0fc7930c0fc4b7b8af54f060 100644
--- a/Source/core/rendering/RenderBoxModelObject.cpp
+++ b/Source/core/rendering/RenderBoxModelObject.cpp
@@ -934,7 +934,7 @@ IntSize RenderBoxModelObject::calculateFillTileSize(const FillLayer* fillLayer,
             float verticalScaleFactor = imageIntrinsicSize.height()
                 ? static_cast<float>(positioningAreaSize.height()) / imageIntrinsicSize.height() : 1;
             float scaleFactor = type == Contain ? min(horizontalScaleFactor, verticalScaleFactor) : max(horizontalScaleFactor, verticalScaleFactor);
-            return IntSize(max(1, static_cast<int>(imageIntrinsicSize.width() * scaleFactor)), max(1, static_cast<int>(imageIntrinsicSize.height() * scaleFactor)));
+            return IntSize(max(1l, lround(imageIntrinsicSize.width() * scaleFactor)), max(1l, lround(imageIntrinsicSize.height() * scaleFactor)));
        }
     }