Count a page load time with selenium webdriver

Suppose their is a situation to check time taken for a web page to load. e.g., Check login time into gmail.

import java.awt.AWTException;
import java.io.IOException;
import org.openqa.selenium.WebDriver;
import org.openqa.selenium.firefox.FirefoxDriver;

public class TrackWebtime {
 public static void main(String[] args) throws IOException, AWTException{

 WebDriver driver =new FirefoxDriver();
 driver.get("http://www.gmail.com");
 
 long start = System.currentTimeMillis();

 driver.findElement(By.id("Email")).clear();
 driver.findElement(By.id("Email")).sendKeys("username");
 driver.findElement(By.id("Passwd")).clear();
 driver.findElement(By.id("Passwd")).sendKeys("password");

 Robot robot = new Robot();
 robot.keyPress(java.awt.event.KeyEvent.VK_ENTER);

 long finish = System.currentTimeMillis();
 
 long TotalTime = finish - start;

 System.out.println("Total Time for page load - "+TotalTime);

 }
}