message: we donot have to recreate viewerHistory.
diff: @@ -15,7 +15,7 @@ document.addEventListener('webviewerloaded', () => {
  PDFViewerApplication.isViewerEmbedded = false
  })
  -let viewerHistory = new ViewerHistory()
  +const viewerHistory = new ViewerHistory()
  const pdfFilePrefix = 'pdf..'
  @@ -140,9 +140,6 @@ function setupWebSocket() {
  PDFViewerApplication.pdfViewer.spreadMode = data.spreadMode
  document.getElementById('viewerContainer').scrollTop = data.scrollTop
  document.getElementById('viewerContainer').scrollLeft = data.scrollLeft
  - viewerHistory = new ViewerHistory()
  - viewerHistory._history = data.viewerHistory.history
  - viewerHistory._currentIndex = data.viewerHistory.currentIndex
  break
  case 'params':
  if (data.scale) {
  