Update Polymer from 1.2.1 -> 1.2.3

third_party/polymer/v1_0/components-chromium/paper-slider/bower.json

 {
   "name": "paper-slider",
-  "version": "1.0.7",
+  "version": "1.0.8",
   "description": "A material design-style slider",
   "license": "http://polymer.github.io/LICENSE.txt",
   "authors": "The Polymer Authors",
   "keywords": [
     "web-components",
     "polymer",
     "slider",
     "control"
   ],
-  "main": [
-    "paper-slider.html"
-  ],
+  "main": "paper-slider.html",
   "repository": {
     "type": "git",
     "url": "git://github.com/PolymerElements/paper-slider.git"
   },
+  "ignore": [],
   "dependencies": {
     "polymer": "Polymer/polymer#^1.0.0",
     "paper-input": "PolymerElements/paper-input#^1.0.0",
     "paper-progress": "PolymerElements/paper-progress#^1.0.0",
     "iron-flex-layout": "PolymerElements/iron-flex-layout#^1.0.0",
     "paper-styles": "PolymerElements/paper-styles#^1.0.0",
     "paper-ripple": "PolymerElements/paper-ripple#^1.0.0",
     "iron-behaviors": "PolymerElements/iron-behaviors#^1.0.0",
     "paper-behaviors": "PolymerElements/paper-behaviors#^1.0.0",
     "iron-a11y-keys-behavior": "PolymerElements/iron-a11y-keys-behavior#^1.0.0",
     "iron-form-element-behavior": "PolymerElements/iron-form-element-behavior#^1.0.0"
   },
   "devDependencies": {
     "iron-component-page": "PolymerElements/iron-component-page#^1.0.0",
     "test-fixture": "PolymerElements/test-fixture#^1.0.0",
     "iron-test-helpers": "polymerelements/iron-test-helpers#^1.0.0",
-    "web-component-tester": "*",
+    "web-component-tester": "polymer/web-component-tester#^3.4.0",
     "webcomponentsjs": "webcomponents/webcomponentsjs#^0.7.0"
   }
 }