Compile print_preview, part 3: reduce down to 185 errors

chrome/browser/resources/print_preview/data/capabilities_holder.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 cr.define('print_preview', function() {
   'use strict';
 
   /**
    * Mutable reference to a CDD object.
    * @constructor
    */
   function CapabilitiesHolder() {
     /**
      * Reference to the capabilities object.
-     * @type {print_preview.Cdd}
+     * @type {?print_preview.Cdd}

[Aleksey Shlyapnikov, 2014/09/22 22:00:40]

I thought objects are nullable by default, why do you need '?' here?

[Vitaly Pavlenko, 2014/09/22 22:33:11]

Well, objects are, but typedefed objects aren't:
https://gist.github.com/vpavlenko/8845b2b4c06a2e3a22ba

tbreisacher@ from the compiler team thinks it's intentional and personally
recommends to put "?" or "!" every time.

      * @private
      */
     this.capabilities_ = null;
   };
 
   CapabilitiesHolder.prototype = {
-    /** @return {print_preview.Cdd} The instance held by the holder. */
+    /** @return {?print_preview.Cdd} The instance held by the holder. */
     get: function() {
       return this.capabilities_;
     },
 
     /**
-     * @param {!print_preview.Cdd} capabilities New instance to put into the
+     * @param {?print_preview.Cdd} capabilities New instance to put into the

[Aleksey Shlyapnikov, 2014/09/22 22:00:40]

Why did you replace '!' with '?'? The idea was that you can only set it to valid
capabilities.

[Vitaly Pavlenko, 2014/09/22 22:33:11]

Sorry about that, reverted.

      *     holder.
      */
     set: function(capabilities) {
       this.capabilities_ = capabilities;
     }
   };
 
   // Export
   return {
     CapabilitiesHolder: CapabilitiesHolder
   };
 });