Bug 988931 - Fix some race conditions in the devtools. r=ochameau

toolkit/devtools/server/child.js

@@ -9,6 +9,7 @@ let chromeGlobal = this;
 // Encapsulate in its own scope to allows loading this frame script
 // more than once.
 (function () {
+  let Cu = Components.utils;
   let { devtools } = Cu.import("resource://gre/modules/devtools/Loader.jsm", {});
   const DevToolsUtils = devtools.require("devtools/toolkit/DevToolsUtils.js");
   const {DebuggerServer, ActorPool} = Cu.import("resource://gre/modules/devtools/dbg-server.jsm", {});

toolkit/devtools/server/main.js

@@ -39,6 +39,7 @@ Cu.import("resource://gre/modules/reflect.jsm");
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 let wantLogging = Services.prefs.getBoolPref("devtools.debugger.log");
 
+Cu.import("resource://gre/modules/commonjs/sdk/core/promise.js");
 Cu.import("resource://gre/modules/jsdebugger.jsm");
 addDebuggerToGlobal(this);