[polymer,web_components] release updated platform.js and corresponding polymer.js
[polymer,web_components] release updated platform.js and corresponding polymer.js

R=sigmund@google.com

Review URL: https://codereview.chromium.org//223903006

git-svn-id: 8bf572593e2315231c3a5579ba5e0157b876ec17@34718 260f80e4-7a28-3924-810f-c04153c831b5

dart-archive/web-components,dart-lang/web-components,ronlobo/web-components,dart-lang/web-components,dart-archive/web-components,dart-lang/web-components,ronlobo/web-components,ronlobo/web-components,dart-archive/web-components