Chrome comes bundled with Flash now… Great, but how do I install the Flash debug player?
In current Chrome (version 47) you don't see installed debug flash player version. You will see only bundled flash player that goes with the browser.
Replacing file as replied here by @dimkin is working. But during update, Chrome will overwrite files and you need to repeat it once in a while.
If you create shortcut for Chrome with command line argument --disable-bundled-ppapi-flash, it will ignore bundled flash player. And if you have Debug version installed, Chrome will use it. You will see it in chrome://plugins/: