Detect Chrome running in headless mode from JavaScript

With the release of Chrome 59, "headless" mode is now available in stable builds for Linux and macOS (and soon also Windows with Chrome 60). This allows us to run a full-featured version of Chrome without any visible UI, a great capability to have for automated testing. More details here.

chrome --headless --disable-gpu --dump-dom http://ift.tt/1jBnDYz

In my JavaScript test runner, I like to record as much information as possible about the browser being used, to help isolate issues. For example, I record many of the properties of navigator, including the current browser plugins:

JSON.stringify(Array.from(navigator.plugins).map(p => p.name))

["Chrome PDF Viewer","Widevine Content Decryption Module","Shockwave Flash","Native Client","Chrome PDF Viewer"]

My understanding is that Chrome should behave identically in headless mode, but I have enough experience to be skeptical of a new feature that may significantly change the rendering pipeline.

For now, I am going to run tests in both modes. I would like to the test runner to record whether headless mode is being used. I could pass this information in the test configurations, but I'd rather have a pure JavaScript solution that I can build into the test runner itself. However, I haven't been able to find any browser interface that reveals whether headless mode is active.

Is there any way to detect if Chrome is running in headless mode from JavaScript?