Problems attempting to import a jsm resource: AddonManager

Question

I have a function in my Greasemonkey Script to access the Firefox AddonManager API. According to my log statements, though, I can never actually import it.

function getScripts() {
  console.log("step 1");
  Cu.import("resource://gre/modules/AddonManager.jsm");  
  console.log("step 2");
  AddonManager.getAddonsByTypes(["greasemonkey-user-script"], function(a) {
    var arr = []
    for (var i = 0; i < a.length; i++) {
      arr[i] = a[i].name;
      console.log(arr[i]);
    }
  });
}