Catch gas estimate errors

There were two cases where bad gas estimate data was resulting in
crashes. These two places have been wrapped in a `try ... catch` to
handle the absence of gas estimate data.

The errors are still reported to Sentry so that we can track down the
root cause of this corrupted gas estimate data at some point in the
future. We plan on adding additional context to Sentry soon that should
help with this.

Fixes #8992

ui/app/components/app/gas-customization/gas-modal-page-container/gas-modal-page-container.container.js

@@ -1,5 +1,6 @@
 import { connect } from 'react-redux'
 import GasModalPageContainer from './gas-modal-page-container.component'
+import { captureException } from '@sentry/browser'
 import {
   hideModal,
   setGasLimit,
@@ -124,6 +125,12 @@ const mapStateToProps = (state, ownProps) => {
     conversionRate,
   })
 
+  let currentTimeEstimate = ''
+  try {
+    currentTimeEstimate = getRenderableTimeEstimate(customGasPrice, gasPrices, estimatedTimes)
+  } catch (error) {
+    captureException(error)
+  }
 
   return {
     hideBasic,
@@ -134,7 +141,7 @@ const mapStateToProps = (state, ownProps) => {
     customGasLimit: calcCustomGasLimit(customModalGasLimitInHex),
     customGasTotal,
     newTotalFiat,
-    currentTimeEstimate: getRenderableTimeEstimate(customGasPrice, gasPrices, estimatedTimes),
+    currentTimeEstimate,
     blockTime: getBasicGasEstimateBlockTime(state),
     customPriceIsSafe: isCustomPriceSafe(state),
     maxModeOn,

ui/app/hooks/useTransactionTimeRemaining.js

@@ -3,10 +3,10 @@ import { hexWEIToDecGWEI } from '../helpers/utils/conversions.util'
 import { useSelector } from 'react-redux'
 import { useRef, useEffect, useState, useMemo } from 'react'
 import { isEqual } from 'lodash'
+import { captureException } from '@sentry/browser'
 import { getRawTimeEstimateData } from '../helpers/utils/gas-time-estimates.util'
 import { getCurrentLocale } from '../ducks/metamask/metamask'
 
-
 /**
  * Calculate the number of minutes remaining until the transaction completes.
  * @param {number} initialTimeEstimate - timestamp for the projected completion time
@@ -55,10 +55,15 @@ export function useTransactionTimeRemaining (
   // Memoize this value so it can be used as a dependency in the effect below
   const initialTimeEstimate = useMemo(() => {
     const customGasPrice = Number(hexWEIToDecGWEI(currentGasPrice))
-    const {
-      newTimeEstimate,
-    } = getRawTimeEstimateData(customGasPrice, gasPrices, estimatedTimes)
-    return newTimeEstimate
+    try {
+      const {
+        newTimeEstimate,
+      } = getRawTimeEstimateData(customGasPrice, gasPrices, estimatedTimes)
+      return newTimeEstimate
+    } catch (error) {
+      captureException(error)
+      return NaN
+    }
   }, [ currentGasPrice, gasPrices, estimatedTimes ])
 
   useEffect(() => {