Fix a bug which causes webchannel to close prematurely when HTTP stre…

…am is aborted.

RELNOTES: n/a

PiperOrigin-RevId: 427648028
Change-Id: I27c0e4133301977f6fd3d8f8beeb24ecaca6d48a

closure/goog/labs/net/webchannel/webchannelbase.js

@@ -2047,13 +2047,14 @@ WebChannelBase.prototype.clearDeadBackchannelTimer_ = function() {
  * failed request.
  * @param {?ChannelRequest.Error} error The error code for the
  * failed request.
+ * @param {number} statusCode The last HTTP status code.
  * @return {boolean} Whether or not the error is fatal.
  * @private
  */
-WebChannelBase.isFatalError_ = function(error) {
+WebChannelBase.isFatalError_ = function(error, statusCode) {
  'use strict';
  return error == ChannelRequest.Error.UNKNOWN_SESSION_ID ||
- error == ChannelRequest.Error.STATUS;
+ (error == ChannelRequest.Error.STATUS && statusCode > 0);
 };
 
 
@@ -2101,7 +2102,7 @@ WebChannelBase.prototype.onRequestComplete = function(request) {
  // Else unsuccessful. Fall through.
 
  const lastError = request.getLastError();
- if (!WebChannelBase.isFatalError_(lastError)) {
+ if (!WebChannelBase.isFatalError_(lastError, this.lastStatusCode_)) {
  // Maybe retry.
  const self = this;
  this.channelDebug_.debug(function() {