Debug wp_oembed-problems

gistfile1.php

<?php

require_once("wp-load.php");

add_action('http_api_debug', 'test_http_api_debug', 10, 5);
add_filter('oembed_remote_get_args', 'test_oembed_remote_get_args', 10, 2);
add_filter('oembed_fetch_url', 'test_oembed_fetch_url', 10, 3);


$embed_code = wp_oembed_get('http://vimeo.com/75343493');
echo "<h2>result</h2>", PHP_EOL;

var_dump_html($embed_code);

print($embed_code);

function var_dump_html($var) {
        ob_start();
        var_dump($var);
        $result = ob_get_contents();
        ob_end_clean();
        echo "<pre>", htmlspecialchars($result), "</pre>", PHP_EOL;
}

function test_oembed_remote_get_args($args, $url) {
        echo "<h2>oembed_remote_get_args</h2> $url<br>", PHP_EOL;
        return $args;
}


function test_oembed_fetch_url($provider, $url, $args) {
        echo "<h2>oembed_fetch_url</h2> $provider, $url <br><pre>", PHP_EOL;
        var_dump_html($args);
        echo "</pre>end oembed_fetch_url<br>", PHP_EOL;
        return $provider;
}

function test_http_api_debug($response, $context, $class, $args, $url) {
        echo "<h2>http_api_debug</h2> context=$context, class=$class, url=$url <br>", PHP_EOL;
        echo "args: "; var_dump_html($args);

        if(is_wp_error($response)) {
                echo "error: ", PHP_EOL;
                $messages = $response->get_error_messages();
                var_dump_html($messages);
        } else {
                echo "response:";
                var_dump_html($response);
        }
}