Calculate load time in index.js

Do it previously in window-bootstrap caused several things to not be
included such as requiring coffee script and atom shell modules.

Now it is a much more accurate representation of on load time.

src/window-bootstrap.coffee

@@ -1,14 +1,10 @@
 # Like sands through the hourglass, so are the days of our lives.
-startTime = Date.now()
-
 require './window'
 
 Atom = require './atom'
 window.atom = Atom.loadOrCreate('editor')
 atom.initialize()
 atom.startEditorWindow()
-window.atom.loadTime = Date.now() - startTime
-console.log "Window load time: #{atom.getWindowLoadTime()}ms"
 
 # Workaround for focus getting cleared upon window creation
 windowFocused = ->

static/index.js

@@ -1,5 +1,7 @@
 window.onload = function() {
   try {
+    var startTime = Date.now();
+
     // Skip "?loadSettings=".
     var loadSettings = JSON.parse(decodeURIComponent(location.search.substr(14)));
 
@@ -30,7 +32,12 @@ window.onload = function() {
     require('../src/coffee-cache').register();
 
     require(loadSettings.bootstrapScript);
-    require('ipc').sendChannel('window-command', 'window:loaded')
+    require('ipc').sendChannel('window-command', 'window:loaded');
+
+    if (global.atom) {
+      global.atom.loadTime = Date.now() - startTime;
+      console.log('Window load time: ' + global.atom.getWindowLoadTime() + 'ms');
+    }
   }
   catch (error) {
     var currentWindow = require('remote').getCurrentWindow();