Update Polymer components.

third_party/polymer/components/web-animations-js/docs/support.md

+
+Getting the polyfill
+--------------------
+
+There are three ways to get a copy of the polyfill:
+
+1. Download and use the `web-animations.min.js` file directly from this repository
+1. Using npm: Add [`web-animations-js`](https://www.npmjs.com/package/web-animations-js) to your `package.json`
+1. Using Bower: Add `web-animations/web-animations-js` to your `bower.json`
+
+Browser support
+---------------
+
+The polyfill is supported on modern versions of all major browsers, including:
+
+* Chrome 55+
+* Firefox 27+
+* IE10+ (including Edge)
+* Safari (iOS) 7.1+
+* Safari (Mac) 9+
+
+Native fallback
+---------------
+
+When the polyfill runs on a browser that implements `Element.animate()` and
+`Animation` playback control, it will detect and use the underlying native
+features for better performance.
+
+Features
+--------
+
+The `web-animations.min.js` polyfill target tracks the Web Animations features
+that are supported natively in browsers. These include:
+
+* Element.animate()
+* Timing input (easings, duration, fillMode, etc.) for animation effects
+* Playback control (play, pause, reverse, currentTime, cancel, onfinish)
+* Support for animating CSS properties
+
+Caveat: Prefix handling
+-----------------------
+
+The polyfill will automatically detect the correctly prefixed name to use when
+writing animated properties back to the platform. Where possible, the polyfill
+will only accept unprefixed versions of experimental features. For example:
+
+```js
+element.animate({transform: ['none', 'translateX(100px)']}, 1000);
+```
+
+will work in all browsers that implement a conforming version of transform, but
+
+```js
+element.animate({webkitTransform: ['none', 'translateX(100px)']}, 1000);
+```
+
+will not work anywhere.
+
+Process for breaking changes
+----------------------------
+
+When we make a potentially breaking change to the polyfill's API
+surface (like a rename) we will, where possible, continue supporting the
+old version, deprecated, for three months, and ensure that there are
+console warnings to indicate that a change is pending. After three
+months, the old version of the API surface (e.g. the old version of a
+function name) will be removed. *If you see deprecation warnings, you
+can't avoid them by not updating*.
+