Add DPI option selection to Print Preview.

chrome/browser/resources/print_preview/data/ticket_items/dpi.js

+// Copyright 2014 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.ticket_items', function() {
+  'use strict';
+
+  /**
+   * DPI ticket item.
+   * @param {!print_preview.AppState} appState App state used to persist DPI
+   *     selection.
+   * @param {!print_preview.DestinationStore} destinationStore Destination store
+   *     used to determine if a destination has the DPI capability.
+   * @constructor
+   * @extends {print_preview.ticket_items.TicketItem}
+   */
+  function Dpi(appState, destinationStore) {
+    print_preview.ticket_items.TicketItem.call(
+        this,
+        appState,
+        print_preview.AppState.Field.DPI,
+        destinationStore);
+  };
+
+  Dpi.prototype = {
+    __proto__: print_preview.ticket_items.TicketItem.prototype,
+
+    /** @override */
+    wouldValueBeValid: function(value) {
+      if (!this.isCapabilityAvailable())
+        return false;
+      return this.capability.option.some(function(option) {
+        return option.horizontal_dpi == value.horizontal_dpi &&
+               option.vertical_dpi == value.vertical_dpi &&
+               option.vendor_id == value.vendor_id;
+      });
+    },
+
+    /** @override */
+    isCapabilityAvailable: function() {
+      return !!this.capability &&
+             !!this.capability.option &&
+             this.capability.option.length > 1;
+    },
+
+    /** @override */
+    isValueEqual: function(value) {
+      var myValue = this.getValue();
+      return myValue.horizontal_dpi == value.horizontal_dpi &&
+             myValue.vertical_dpi == value.vertical_dpi &&
+             myValue.vendor_id == value.vendor_id;
+    },
+
+    /** @return {Object} DPI capability of the selected destination. */
+    get capability() {
+      var destination = this.getSelectedDestInternal();
+      return (destination &&
+              destination.capabilities &&
+              destination.capabilities.printer &&
+              destination.capabilities.printer.dpi) ||
+             null;
+    },
+
+    /** @override */
+    getDefaultValueInternal: function() {
+      var defaultOptions = this.capability.option.filter(function(option) {
+        return option.is_default;
+      });
+      return defaultOptions.length > 0 ? defaultOptions[0] : null;
+    },
+
+    /** @override */
+    getCapabilityNotAvailableValueInternal: function() {
+      return {};
+    }
+  };
+
+  // Export
+  return {
+    Dpi: Dpi
+  };
+});