add method for printing found chrome path

[brendankenny]

Using Lighthouse user flows, I find myself alternating between being fine with the version of Chrome shipped with puppeteer and needing the Canary installed on my machine, depending on what I'm doing, but it's awkward to set the path manually, and it's not portable (e.g. for sample code)

chrome-launcher is already set up to find Canary, so I've been wanting a way to be able to easily run something like

const browser = await puppeteer.launch({
  headless: false,
  executablePath: chromeLauncher.getChromePath(),
});

I don't see any non-ugly way of reaching into chrome-launcher to do this (someone correct me if I'm wrong), so this PR exposes a function to do this.

Also adds a bin option as I've also wanted it on the command line, e.g. CHROME_PATH="$(npm exec print-chrome-path)". Please suggest better approaches for that too, if there are any :)

[adamraine]

This is better, but importing chrome-launcher everywhere in samples just to get the path to Canary doesn't seem ideal. Maybe we could add a getChromePath function to the FR API?

[paulirish]

add this file plz :)

[connorjclark]

I assume this was chmod +x'd, although I don't know if there is a way to confirm that in GH ui.

related, benefits to using shebang vs just setting the bin script to node bin/print-chrome-path.js ?

[brendankenny]

I assume this was chmod +x'd, although I don't know if there is a way to confirm that in GH ui

npm/yarn does the chmod on install

related, benefits to using shebang vs just setting the bin script to node bin/print-chrome-path.js ?

unlike script entries, bin entries are just filenames that are symlinked into node_modules/.bin, so need the shebang

[connorjclark]

TIL, thx!