[third_party] add polymer 1.2.3

polymer_1.2.3/bower_components/iron-selector/iron-multi-selectable.html

 <!--
 @license
 Copyright (c) 2015 The Polymer Project Authors. All rights reserved.
 This code may only be used under the BSD style license found at http://polymer.github.io/LICENSE.txt
 The complete set of authors may be found at http://polymer.github.io/AUTHORS.txt
 The complete set of contributors may be found at http://polymer.github.io/CONTRIBUTORS.txt
 Code distributed by Google as part of the polymer project is also
 subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 -->
 
@@ skipping 54 matching lines @@
         }
       } else {
         this.selected = value;
       }
     },
 
     multiChanged: function(multi) {
       this._selection.multi = multi;
     },
 
+    get _shouldUpdateSelection() {
+      return this.selected != null ||
+        (this.selectedValues != null && this.selectedValues.length);
+    },
+
     _updateSelected: function() {
       if (this.multi) {
         this._selectMulti(this.selectedValues);
       } else {
         this._selectSelected(this.selected);
       }
     },
 
     _selectMulti: function(values) {
       this._selection.clear();
@@ skipping 11 matching lines @@
       } else {
         this._setSelectedItems([s]);
         this._setSelectedItem(s);
       }
     },
 
     _toggleSelected: function(value) {
       var i = this.selectedValues.indexOf(value);
       var unselected = i < 0;
       if (unselected) {
-        this.selectedValues.push(value);
+        this.push('selectedValues',value);
       } else {
-        this.selectedValues.splice(i, 1);
+        this.splice('selectedValues',i,1);
       }
       this._selection.setItemSelected(this._valueToItem(value), unselected);
     }
   };
 
   /** @polymerBehavior */
   Polymer.IronMultiSelectableBehavior = [
     Polymer.IronSelectableBehavior,
     Polymer.IronMultiSelectableBehaviorImpl
   ];
 
 </script>