code: function initiateAutoUpdate(updateParams) {
          _updateParams = updateParams;
          downloadAttemptsRemaining = MAX_DOWNLOAD_ATTEMPTS;
  
          initializeState()
              .done(function () {
  
                   var setUpdateInProgress = function() {
                      var initNodeFn = function () {
                          isAutoUpdateInitiated = true;
                          postMessageToNode(MessageIds.INITIALIZE_STATE, _updateParams);
                      };
  
                      if (updateJsonHandler.get('latestBuildNumber') !== _updateParams.latestBuildNumber) {
                          setUpdateStateInJSON('latestBuildNumber', _updateParams.latestBuildNumber)
                              .done(initNodeFn);
                      } else {
                          initNodeFn();
                      }
                  };
  
                  checkIfAnotherSessionInProgress()
                      .done(function(inProgress) {
                          if(inProgress) {
                              UpdateInfoBar.showUpdateBar({
                                  type: "error",
                                  title: Strings.AUTOUPDATE_ERROR,
                                  description: Strings.AUTOUPDATE_IN_PROGRESS
                              });
                          } else {
                               setUpdateStateInJSON("autoUpdateInProgress", true)
                                  .done(setUpdateInProgress);
  
                          }
                      })
                      .fail(function() {
                          setUpdateStateInJSON("autoUpdateInProgress", true)
                              .done(setUpdateInProgress);
  
                      });
  
              })
              .fail(function () {
                  UpdateInfoBar.showUpdateBar({
                      type: "error",
                      title: Strings.INITIALISATION_FAILED,
                      description: ""
                  });
              });
      }
docs: Handles the auto update event, which is triggered when user clicks GetItNow in UpdateNotification dialog
  @param {object} updateParams - json object containing update information {
  installerName - name of the installer
  downloadURL - download URL
  latestBuildNumber - build number
  checksum - checksum }