Is it possible to export HAR using chromedriver similar to what I can do with netexpert+firebug with Firefox?
Yes, using BrowsermobProxy you can generate HAR file using chromedriver.
Here is a script in python to programatically generate HAR file using Selenium, BrowserMob Proxy and chromedriver. Python Packages for selenium and browsermob-proxy are needed to run this script.
from browsermobproxy import Server
from selenium import webdriver
import os
import json
import urlparse
server = Server("path/to/browsermob-proxy")
server.start()
proxy = server.create_proxy()
chromedriver = "path/to/chromedriver"
os.environ["webdriver.chrome.driver"] = chromedriver
url = urlparse.urlparse (proxy.proxy).path
chrome_options = webdriver.ChromeOptions()
chrome_options.add_argument("--proxy-server={0}".format(url))
driver = webdriver.Chrome(chromedriver,chrome_options =chrome_options)
proxy.new_har("http://stackoverflow.com", options={'captureHeaders': True})
driver.get("http://stackoverflow.com")
result = json.dumps(proxy.har, ensure_ascii=False)
print result
proxy.stop()
driver.quit()