Issue 2850 - Get rid of synchronous XMLHttpRequest on startup, embed JSON files directly instead

bootstrap.js.tmpl

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
 const Cc = Components.classes;
 const Ci = Components.interfaces;
 const Cr = Components.results;
 const Cu = Components.utils;
 
 let {Services, atob, btoa, File, TextDecoder, TextEncoder} = Cu.import("resource://gre/modules/Services.jsm", null);
@@ skipping 65 matching lines @@
       scope[list[i]] = null;
   }
   require.scopes = null;
   addonData = null;
 }
 
 function install(params, reason) {}
 
 function uninstall(params, reason)
 {
-  {%- if hasVersionPref %}
+  {%- if 'currentVersion' in jsonRequires.get('prefs.json', {}).get('defaults', {}) %}
   const ADDON_UNINSTALL = 6;  // https://developer.mozilla.org/en/Extensions/Bootstrapped_extensions#Reason_constants
   if (reason == ADDON_UNINSTALL)
   {
     // Users often uninstall/reinstall extension to "fix" issues. Clear current
     // version number on uninstall to rerun first-run actions in this scenario.
     Services.prefs.clearUserPref("extensions.{{metadata.get('general', 'basename')}}.currentVersion");
   }
   {%- endif %}
 }
 
@@ skipping 69 matching lines @@
       });
       {%- endif %}
       Services.scriptloader.loadSubScript(url, scopes[module]);
     {%- if 'info' in requires %}
     }
     {%- endif %}
   }
   return scopes[module].exports;
 }
 require.scopes = Object.create(null);
+{%- for name, data in jsonRequires.iteritems() %}
+require.scopes[{{name|json}}] = {exports: {{data|json}}};
+{%- endfor %}
 
 {%- if hasChromeRequires %}
 Cu.import("resource://gre/modules/XPCOMUtils.jsm");
 
 let RequireObserver =
 {
   observe: function(subject, topic, data)
   {
     if (topic == "{{metadata.get('general', 'basename')}}-require")
     {
       subject.wrappedJSObject.exports = require(data);
     }
   },
 
   QueryInterface: XPCOMUtils.generateQI([Ci.nsISupportsWeakReference, Ci.nsIObserver])
 };
 {%- endif %}