Roll Polymer from 1.5.0 -> 1.6.0 to pick up native CSS custom props

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

 {
   "name": "iron-resizable-behavior",
-  "version": "1.0.3",
+  "version": "1.0.4",
   "license": "http://polymer.github.io/LICENSE.txt",
   "description": "Coordinates the flow of resizeable elements",
   "private": true,
   "main": "iron-resizable-behavior.html",
   "authors": [
     "The Polymer Authors"
   ],
   "keywords": [
     "web-components",
     "polymer",
     "iron",
     "behavior"
   ],
   "repository": {
     "type": "git",
     "url": "git://github.com/PolymerElements/iron-resizable-behavior.git"
   },
   "dependencies": {
-    "polymer": "Polymer/polymer#^1.0.0"
+    "polymer": "Polymer/polymer#^1.1.0"
   },
   "devDependencies": {
     "iron-component-page": "polymerelements/iron-component-page#^1.0.0",
     "test-fixture": "polymerelements/test-fixture#^1.0.0",
     "web-component-tester": "^4.0.0",
     "webcomponentsjs": "webcomponents/webcomponentsjs#^0.7.0"
   },
   "ignore": []
 }