To enable Flash plugin in Chrome browser, you should follow several steps:

1. Download standard Chrome plugin from Adobe website and install it.
2. Add argument for runnning Chrome engine in project settings --enable-system-flash --disable-software-rasterizer --disable-smooth-scrolling More info on how to use run arguments can be read in this article Command line arguments for running Chrome engine.
   

1. Disable Plugins emulation in browser profile settings. More info about browser profile settings can be found in this article Browser profile emulation.

After all this actions, Flash will be available for usage. Note that run arguments will be applied to Chrome engine in ProjectMaker after restarting project (pressing Restart button).