[third_party] add polymer 1.2.3

polymer_1.2.3/bower_components/iron-meta/README.md

+
+<!---
+
+This README is automatically generated from the comments in these files:
+iron-meta.html
+
+Edit those files, and our readme bot will duplicate them over here!
+Edit this file, and the bot will squash your changes :)
+
+-->
+
+[![Build Status](https://travis-ci.org/PolymerElements/iron-meta.svg?branch=master)](https://travis-ci.org/PolymerElements/iron-meta)
+
+_[Demo and API Docs](https://elements.polymer-project.org/elements/iron-meta)_
+
+
+##&lt;iron-meta&gt;
+
+
+`iron-meta` is a generic element you can use for sharing information across the DOM tree.
+It uses [monostate pattern](http://c2.com/cgi/wiki?MonostatePattern) such that any
+instance of iron-meta has access to the shared
+information. You can use `iron-meta` to share whatever you want (or create an extension
+[like x-meta] for enhancements).
+
+The `iron-meta` instances containing your actual data can be loaded in an import,
+or constructed in any way you see fit. The only requirement is that you create them
+before you try to access them.
+
+Examples:
+
+If I create an instance like this:
+
+    <iron-meta key="info" value="foo/bar"></iron-meta>
+
+Note that value="foo/bar" is the metadata I've defined. I could define more
+attributes or use child nodes to define additional metadata.
+
+Now I can access that element (and it's metadata) from any iron-meta instance
+via the byKey method, e.g.
+
+    meta.byKey('info').getAttribute('value');
+
+Pure imperative form would be like:
+
+    document.createElement('iron-meta').byKey('info').getAttribute('value');
+
+Or, in a Polymer element, you can include a meta in your template:
+
+    <iron-meta id="meta"></iron-meta>
+    ...
+    this.$.meta.byKey('info').getAttribute('value');
+
+
+
+##&lt;iron-meta-query&gt;
+
+
+`iron-meta` is a generic element you can use for sharing information across the DOM tree.
+It uses [monostate pattern](http://c2.com/cgi/wiki?MonostatePattern) such that any
+instance of iron-meta has access to the shared
+information. You can use `iron-meta` to share whatever you want (or create an extension
+[like x-meta] for enhancements).
+
+The `iron-meta` instances containing your actual data can be loaded in an import,
+or constructed in any way you see fit. The only requirement is that you create them
+before you try to access them.
+
+Examples:
+
+If I create an instance like this:
+
+    <iron-meta key="info" value="foo/bar"></iron-meta>
+
+Note that value="foo/bar" is the metadata I've defined. I could define more
+attributes or use child nodes to define additional metadata.
+
+Now I can access that element (and it's metadata) from any iron-meta instance
+via the byKey method, e.g.
+
+    meta.byKey('info').getAttribute('value');
+
+Pure imperative form would be like:
+
+    document.createElement('iron-meta').byKey('info').getAttribute('value');
+
+Or, in a Polymer element, you can include a meta in your template:
+
+    <iron-meta id="meta"></iron-meta>
+    ...
+    this.$.meta.byKey('info').getAttribute('value');
+
+