Remove workaround for old Windows bug

The code removed is no longer needed as it was fixed in this issue of atom-shell

https://github.com/electron/electron/issues/380

src/main-process/atom-window.coffee

@@ -157,17 +157,6 @@ class AtomWindow
 
     @setupContextMenu()
 
-    if @isSpec
-      # Workaround for https://github.com/atom/atom-shell/issues/380
-      # Don't focus the window when it is being blurred during close or
-      # else the app will crash on Windows.
-      if process.platform is 'win32'
-        @browserWindow.on 'close', => @isWindowClosing = true
-
-      # Spec window's web view should always have focus
-      @browserWindow.on 'blur', =>
-        @browserWindow.focusOnWebView() unless @isWindowClosing
-
   openPath: (pathToOpen, initialLine, initialColumn) ->
     @openLocations([{pathToOpen, initialLine, initialColumn}])