background.js

chrome.browserAction.onClicked.addListener(
    function(tab) { 
        var currentURL = tab.url;
        if (currentURL.indexOf("gyazo") == -1)
            return;
        console.log(currentURL.split("/"));
        var src = "http://i.gyazo.com/" + currentURL.split("/").pop() + ".png";
        var xhr = new XMLHttpRequest();
        xhr.open("GET", "http://qps.ru/api?url=" + src + "&format=text", true);
        xhr.onreadystatechange = function () {
            if (xhr.readyState == 4) {
                console.log(xhr.responseText);
                executeCopy(xhr.responseText);
            }
        }
        xhr.send();
    }
);

function executeCopy(text) {
    var input = document.createElement('textarea');
    document.body.appendChild(input);
    input.value = text;
    input.focus();
    input.select();
    document.execCommand('Copy');
    input.remove();
}

//gyazo short img link