     'contentWindow is not available at this time. It will become available ' +
     'when the page has finished loading.'
 ERROR_MSG_INVALID_PARTITION_ATTRIBUTE = 'Invalid partition attribute.'
+ERROR_MSG_INVALID_PRELOAD_ATTRIBUTE =
+    'Only "file:" or "asar:" protocol is supported in "preload" attribute.'
 
 # Represents the state of the storage partition.
 class Partition

WEB_VIEW_ATTRIBUTE_PARTITION = 'partition'
WEB_VIEW_ATTRIBUTE_NODEINTEGRATION = 'nodeintegration'
WEB_VIEW_ATTRIBUTE_PLUGINS = 'plugins'
AUTO_SIZE_ATTRIBUTES = [
  WEB_VIEW_ATTRIBUTE_AUTOSIZE,
  WEB_VIEW_ATTRIBUTE_MAXHEIGHT,

      storagePartitionId: storagePartitionId
      nodeIntegration: @webviewNode.hasAttribute WEB_VIEW_ATTRIBUTE_NODEINTEGRATION
      plugins: @webviewNode.hasAttribute WEB_VIEW_ATTRIBUTE_PLUGINS
    if @webviewNode.hasAttribute WEB_VIEW_ATTRIBUTE_PRELOAD
      preload = @webviewNode.getAttribute WEB_VIEW_ATTRIBUTE_PRELOAD
      # Get the full path.
      a = document.createElement 'a'
      a.href = preload
      params.preload = a.href
      # Only support file: or asar: protocol.
      protocol = params.preload.substr 0, 5
      unless protocol in ['file:', 'asar:']
        delete params.preload
        console.error ERROR_MSG_INVALID_PRELOAD_ATTRIBUTE
    guestViewInternal.createGuest 'webview', params, (guestInstanceId) =>
      @pendingGuestCreation = false
      unless @elementAttached
