WebRTC only Demo - Cross Platfrom

Let's Play Fun!
CAUTION: still need to fix the "vertical picture"'s cropping
Ref:
1.Basic Tutorial: MDN WebRTC Tutorial
2.Cross Compatibility: Cross-Browser-Compatible-WebRTC
This example is (1) + (2)'s window.URL = window.URL || window.webkitURL || window.mozURL || window.msURL;
This is a light, simple, fast demo of WebRTC picture shot.
Step1: Image Preview Part: