videojs/video.js — pull request #898 by tuchida (2013-12-16 23:36:27+00:00)
Title: Remove added userActivity_ to global

I browsed this html.
```html

```

```window.userAcitvity_``` is undefined at first. But it is now true If I click on the video.
Because ```onMouseActivity();``` is not specified thisValue, thisValue in the ```reportUserActivity``` is window.