Issue 2950 - Don`t rely on Services.mm, it isn`t available before Gecko 39

lib/main.js

Index: lib/main.js
===================================================================
--- a/lib/main.js
+++ b/lib/main.js
@@ -43,20 +43,22 @@ request.addEventListener("load", functio
   let styleURI = Services.io.newURI("data:text/css," + encodeURIComponent(data), null, null);
   styleService.loadAndRegisterSheet(styleURI, Ci.nsIStyleSheetService.USER_SHEET);
   onShutdown.add(() => styleService.unregisterSheet(styleURI, Ci.nsIStyleSheetService.USER_SHEET));
 }, false);
 request.send(null);
 
 // Load our developer tools actor
 let frameScript = "chrome://elemhidehelper/content/frameScript.js?" + elementMarkerClass;
-Services.mm.loadFrameScript(frameScript, true);
+let messageManager = Cc["@mozilla.org/globalmessagemanager;1"]
+  .getService(Ci.nsIFrameScriptLoader);
+messageManager.loadFrameScript(frameScript, true);
 onShutdown.add(() => {
-  Services.mm.removeDelayedFrameScript(frameScript);
-  Services.mm.broadcastAsyncMessage("ElemHideHelper:Shutdown");
+  messageManager.removeDelayedFrameScript(frameScript);
+  messageManager.QueryInterface(Ci.nsIMessageBroadcaster).broadcastAsyncMessage("ElemHideHelper:Shutdown");
 });
 
 // Load overlay asynchonously and start attaching to windows once done
 request = Cc["@mozilla.org/xmlextras/xmlhttprequest;1"].createInstance(Ci.nsIJSXMLHttpRequest);
 request.open("GET", "chrome://elemhidehelper/content/overlay.xul");
 request.addEventListener("load", function(event)
 {
   if (onShutdown.done)