Adding Gravity Form With if(is_page) Is Not Working

if you got following in your functions.php

function add_split_test_forms()
{
    if (is_page('Homepage')):
    gravity_form(19, false, false, false, '', false);
    endif;
}

you will at least need to run this function once: add a line add_split_test_forms() in your functions.php.

if your condition if (is_page('Homepage')): is correct. (I prefer if ( is_front_page()): should also work.)
Then your form should appear in the markup, like you said.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)