Process null capabilities as a capability fetch failure.

chrome/browser/resources/print_preview/native_layer.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.exportPath('print_preview');
 
 /**
  * @typedef {{selectSaveAsPdfDestination: boolean,
  *            layoutSettings.portrait: boolean,
  *            pageRange: string,
@@ skipping 532 matching lines @@
       this.dispatchEvent(localDestsSetEvent);
     },
 
     /**
      * Called when native layer gets settings information for a requested local
      * destination.
      * @param {Object} settingsInfo printer setting information.
      * @private
      */
     onUpdateWithPrinterCapabilities_: function(settingsInfo) {
+      assert(settingsInfo.capabilities,
+          'Capabilities update without capabilites');
       var capsSetEvent = new Event(NativeLayer.EventType.CAPABILITIES_SET);
       capsSetEvent.settingsInfo = settingsInfo;
       this.dispatchEvent(capsSetEvent);
     },
 
     /**
      * Called when native layer gets settings information for a requested local
      * destination.
      * @param {string} destinationId Printer affected by error.
      * @private
@@ skipping 541 matching lines @@
       return this.serializedDefaultDestinationSelectionRulesStr_;
     }
   };
 
   // Export
   return {
     NativeInitialSettings: NativeInitialSettings,
     NativeLayer: NativeLayer
   };
 });