Introduces HorizontalGrid component

components/chart/y-axis.js

@@ -2,26 +2,12 @@ import React from 'react'
 import PropTypes from 'prop-types'
 import { View } from 'react-native'
 
-import { getTickPositions } from '../helpers/chart'
-
 import SymptomIcon from './symptom-icon'
 import TickList from './tick-list'
 import ChartLegend from './chart-legend'
 
 import styles from './styles'
 
-export function makeHorizontalGrid(columnHeight, symptomRowHeight) {
-  return getTickPositions(columnHeight).map(tick => {
-    return (
-      <View
-        top={tick + symptomRowHeight}
-        {...styles.horizontalGrid}
-        key={tick}
-      />
-    )
-  })
-}
-
 const YAxis = ({ height, symptomsToDisplay, symptomsSectionHeight }) => {
   const symptomIconHeight = symptomsSectionHeight / symptomsToDisplay.length
   return (