Changing default video player in Google Chrome for Android tl;dr

When you open any video, default HTML5 player is used. 

What I want is to make Google Chrome to use custom video player whenever it wants to playback a video

Longer story
My real goal is to stream video content from Android to AppleTV via AirPlay. I found a nice app called streambels which is capable of doing that.

The only problem is when I am trying to watch video on Google Chrome, I can't stream it so if I could change the default video player would allow me to pass the video to broadcasting app. And life would be so great :)
Use Dolphin Browser.  I think what you are asking is impossible for now on Chrome.