Update Polymer from 1.2.1 -> 1.2.3

third_party/polymer/v1_0/components-chromium/iron-flex-layout/bower.json

 {
   "name": "iron-flex-layout",
-  "version": "1.0.5",
+  "version": "1.2.0",
   "description": "Provide flexbox-based layouts",
   "keywords": [
     "web-components",
     "polymer",
     "layout"
   ],
   "main": "iron-flex-layout.html",
   "private": true,
   "license": "http://polymer.github.io/LICENSE.txt",
   "authors": [
     "The Polymer Authors"
   ],
   "repository": {
     "type": "git",
     "url": "git://github.com/PolymerElements/iron-flex-layout.git"
   },
   "dependencies": {
-    "polymer": "Polymer/polymer#^1.0.0"
+    "polymer": "Polymer/polymer#^1.1.0"
   },
   "devDependencies": {
     "paper-styles": "polymerelements/paper-styles#^1.0.0",
     "marked-element": "polymerelements/marked-element#^1.0.0",
     "prism-element": "PolymerElements/prism-element#^1.0.0",
     "webcomponentsjs": "webcomponents/webcomponentsjs#^0.7.0",
     "iron-component-page": "polymerelements/iron-component-page#^1.0.0"
   }
 }