[third_party] add polymer 1.2.3

polymer_1.2.3/bower_components/iron-a11y-keys-behavior/bower.json

 {
   "name": "iron-a11y-keys-behavior",
-  "version": "1.0.4",
+  "version": "1.1.1",
   "description": "A behavior that enables keybindings for greater a11y.",
   "keywords": [
     "web-components",
     "web-component",
     "polymer",
     "a11y",
     "input"
   ],
   "authors": [
     "The Polymer Authors"
   ],
   "repository": {
     "type": "git",
     "url": "git://github.com/PolymerElements/iron-a11y-keys-behavior.git"
   },
   "main": "iron-a11y-keys-behavior.html",
   "license": "http://polymer.github.io/LICENSE.txt",
   "dependencies": {
     "polymer": "Polymer/polymer#^1.0.0"
   },
   "devDependencies": {
     "paper-styles": "PolymerElements/paper-styles#^1.0.2",
     "iron-component-page": "polymerelements/iron-component-page#^1.0.0",
     "iron-test-helpers": "polymerelements/iron-test-helpers#^1.0.0",
     "test-fixture": "polymerelements/test-fixture#^1.0.0",
-    "web-component-tester": "*",
+    "web-component-tester": "polymer/web-component-tester#^3.4.0",
     "webcomponentsjs": "webcomponents/webcomponentsjs#^0.7.0"
-  }
+  },
+  "ignore": []
 }