Roll closure compiler

chrome/browser/resources/md_bookmarks/list.js

 // Copyright 2016 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.
 
 Polymer({
   is: 'bookmarks-list',
 
   behaviors: [
     bookmarks.StoreClient,
   ],
@@ skipping 43 matching lines @@
 
   /** @return {HTMLElement} */
   getDropTarget: function() {
     return this.$.message;
   },
 
   /**
    * Updates `displayedList_` using splices to be equivalent to `newValue`. This
    * allows the iron-list to delete sublists of items which preserves scroll and
    * focus on incremental update.
-   * @param {Array<string>} newValue
-   * @param {Array<string>} oldValue
+   * @param {!Array<string>} newValue
+   * @param {!Array<string>} oldValue
    */
   onDisplayedIdsChanged_: function(newValue, oldValue) {
     if (!oldValue) {

[Dan Beam, 2017/05/24 02:52:42]

hmmmm, how can !oldValue ever succeed if oldValue is !Array<string>?

[dpapad, 2017/05/24 17:45:42]

The problem is that calculateSplices() has two different type annotations (and
they don't agree)

1) In the externs, it expects non-null
inputshttps://github.com/google/closure-compiler/blob/e1417207f4b28005afdfda0a3f2b217f31615029/contrib/externs/polymer-1.0.js#L1501,L1503
2) In the actual Polymer code, it allows null
https://github.com/Polymer/polymer/blob/fe779eaf791647659ac9564e936336102ea3c...

We only care about 1, which based on previous conversation (on internal JSComp
CL), it seems to be more accurate. So the right solution here (I think) is to
cast to the right types at line 73, instead of modifying the type annotations of
onDisplayedIdsChanged_ parameters.

[scottchen, 2017/05/24 20:36:25]

Done.

[scottchen, 2017/05/24 20:36:25]

Acknowledged.

       this.displayedList_ = this.displayedIds_.map(function(id) {
         return {id: id};
       });
     } else {
       var splices = Polymer.ArraySplice.calculateSplices(newValue, oldValue);
       splices.forEach(function(splice) {
         // TODO(calamity): Could use notifySplices to improve performance here.
         var additions =
             newValue.slice(splice.index, splice.index + splice.addedCount)
                 .map(function(id) {
@@ skipping 15 matching lines @@
   /** @private */
   isEmptyList_: function() {
     return this.displayedList_.length == 0;
   },
 
   /** @private */
   deselectItems_: function() {
     this.dispatch(bookmarks.actions.deselectItems());
   },
 });