This test verifies that persistent grid in iframe are positioned correctly.

{
  "gridHighlights": [
    {
      "rotationAngle": 0,
      "writingMode": "horizontal-tb",
      "columnTrackSizes": [
        {
          "x": 158,
          "y": 98,
          "computedSize": 120,
          "authoredSize": "120px"
        },
        {
          "x": 288,
          "y": 98,
          "computedSize": 120,
          "authoredSize": "120px"
        },
        {
          "x": 418,
          "y": 98,
          "computedSize": 120,
          "authoredSize": "120px"
        }
      ],
      "rowTrackSizes": [
        {
          "x": 98,
          "y": 220.5,
          "computedSize": 245,
          "authoredSize": "1fr"
        },
        {
          "x": 98,
          "y": 475.5,
          "computedSize": 245,
          "authoredSize": "1fr"
        }
      ],
      "rows": [
        "M",
        98,
        98,
        "L",
        478,
        98,
        "M",
        478,
        343,
        "L",
        98,
        343,
        "M",
        98,
        353,
        "L",
        478,
        353,
        "M",
        478,
        598,
        "L",
        98,
        598
      ],
      "rowGaps": [
        "M",
        98,
        343,
        "L",
        478,
        343,
        "L",
        478,
        353,
        "L",
        98,
        353,
        "Z"
      ],
      "columns": [
        "M",
        98,
        98,
        "L",
        98,
        598,
        "M",
        218,
        598,
        "L",
        218,
        98,
        "M",
        228,
        98,
        "L",
        228,
        598,
        "M",
        348,
        598,
        "L",
        348,
        98,
        "M",
        358,
        98,
        "L",
        358,
        598,
        "M",
        478,
        598,
        "L",
        478,
        98
      ],
      "columnGaps": [
        "M",
        218,
        98,
        "L",
        228,
        98,
        "L",
        228,
        598,
        "L",
        218,
        598,
        "Z",
        "M",
        348,
        98,
        "L",
        358,
        98,
        "L",
        358,
        598,
        "L",
        348,
        598,
        "Z"
      ],
      "positiveRowLineNumberPositions": [
        {
          "x": 98,
          "y": 98
        },
        {
          "x": 98,
          "y": 348
        },
        {
          "x": 98,
          "y": 598
        }
      ],
      "positiveColumnLineNumberPositions": [
        {
          "x": 98,
          "y": 98
        },
        {
          "x": 223,
          "y": 98
        },
        {
          "x": 353,
          "y": 98
        },
        {
          "x": 478,
          "y": 98
        }
      ],
      "negativeRowLineNumberPositions": [
        {
          "x": 478,
          "y": 98
        },
        {
          "x": 478,
          "y": 348
        },
        {
          "x": 478,
          "y": 598
        }
      ],
      "negativeColumnLineNumberPositions": [
        {
          "x": 98,
          "y": 598
        },
        {
          "x": 223,
          "y": 598
        },
        {
          "x": 353,
          "y": 598
        },
        {
          "x": 478,
          "y": 598
        }
      ],
      "areaNames": {
        "content": [
          "M",
          228,
          353,
          "L",
          478,
          353,
          "L",
          478,
          598,
          "L",
          228,
          598,
          "Z"
        ],
        "header": [
          "M",
          228,
          98,
          "L",
          478,
          98,
          "L",
          478,
          343,
          "L",
          228,
          343,
          "Z"
        ],
        "sidebar": [
          "M",
          98,
          353,
          "L",
          218,
          353,
          "L",
          218,
          598,
          "L",
          98,
          598,
          "Z"
        ]
      },
      "rowLineNameOffsets": [
        {
          "x": 98,
          "y": 598,
          "name": "content-end"
        },
        {
          "x": 98,
          "y": 348,
          "name": "content-start"
        },
        {
          "x": 98,
          "y": 348,
          "name": "header-end"
        },
        {
          "x": 98,
          "y": 98,
          "name": "header-start"
        },
        {
          "x": 98,
          "y": 598,
          "name": "sidebar-end"
        },
        {
          "x": 98,
          "y": 348,
          "name": "sidebar-start"
        }
      ],
      "columnLineNameOffsets": [
        {
          "x": 478,
          "y": 98,
          "name": "content-end"
        },
        {
          "x": 223,
          "y": 98,
          "name": "content-start"
        },
        {
          "x": 478,
          "y": 98,
          "name": "header-end"
        },
        {
          "x": 223,
          "y": 98,
          "name": "header-start"
        },
        {
          "x": 223,
          "y": 98,
          "name": "sidebar-end"
        },
        {
          "x": 98,
          "y": 98,
          "name": "sidebar-start"
        }
      ],
      "gridBorder": [
        "M",
        98,
        98,
        "L",
        478,
        98,
        "L",
        478,
        598,
        "L",
        98,
        598,
        "Z"
      ],
      "gridHighlightConfig": {
        "gridBorderDash": false,
        "rowLineDash": true,
        "columnLineDash": true,
        "showGridExtensionLines": true,
        "showPositiveLineNumbers": true,
        "showNegativeLineNumbers": true,
        "showAreaNames": true,
        "showLineNames": true,
        "gridBorderColor": "rgba(255, 0, 0, 0)",
        "rowLineColor": "rgba(128, 0, 0, 0)",
        "columnLineColor": "rgba(128, 0, 0, 0)",
        "rowGapColor": "rgba(0, 255, 0, 0)",
        "columnGapColor": "rgba(0, 0, 255, 0)",
        "rowHatchColor": "rgba(255, 255, 255, 0)",
        "columnHatchColor": "rgba(128, 128, 128, 0)",
        "areaBorderColor": "rgba(255, 0, 0, 0)",
        "gridBackgroundColor": "rgba(255, 0, 0, 0)"
      },
      "isPrimaryGrid": true
    }
  ]
}