[misc][XWALK-2231] Integrate MediaSource API Demo

- https://github.com/ebidel/html5demos/blob/master/html5-demos.appspot.com/static/media-source.html
  under the Apache License, Version 2.0
- Bug  https://crosswalk-project.org/jira/browse/XWALK-2231
- Task https://crosswalk-project.org/jira/browse/XWALK-2331
[misc] Comment out google fonts and analytics dependency
Merge pull request #821 from zqzhang/zqzhang/XWALK-2231

[misc][XWALK-2231] Integrate MediaSource API Demo