Update Polymer from 1.2.1 -> 1.2.3

third_party/polymer/v1_0/components-chromium/iron-checked-element-behavior/bower.json

 {
   "name": "iron-checked-element-behavior",
-  "version": "1.0.2",
+  "version": "1.0.3",
   "description": "Implements an element that has a checked attribute and can be added to a form",
   "authors": "The Polymer Authors",
   "keywords": [
     "web-components",
     "polymer",
     "iron",
     "behavior"
   ],
-  "main": [
-    "iron-checked-element-behavior.html"
-  ],
+  "main": "iron-checked-element-behavior.html",
   "private": true,
   "repository": {
     "type": "git",
     "url": "git://github.com/PolymerElements/iron-checked-element-behavior.git"
   },
   "license": "http://polymer.github.io/LICENSE.txt",
   "homepage": "https://github.com/PolymerElements/iron-checked-element-behavior",
   "ignore": [],
   "dependencies": {
     "polymer": "Polymer/polymer#^1.0.0",
     "iron-validatable-behavior": "PolymerElements/iron-validatable-behavior#^1.0.0",
     "iron-form-element-behavior": "PolymerElements/iron-form-element-behavior#^1.0.0"
   },
   "devDependencies": {
     "paper-styles": "PolymerElements/paper-styles#^1.0.0",
     "paper-button": "PolymerElements/paper-button#^1.0.0",
     "iron-component-page": "PolymerElements/iron-component-page#^1.0.0",
     "test-fixture": "PolymerElements/test-fixture#^1.0.0",
     "web-component-tester": "*",
     "webcomponentsjs": "webcomponents/webcomponentsjs#^0.7.0"
   }
 }