Firefox on Android always runs power usage tests

[soulgalore]

When I run tests on Firefox on Android I always get a log line like:
CPU / Power usage: 9180

The power usage should be turned off by default, so I think there's a bug.

[gmierz]

@soulgalore I think this is expected since we always gather the CPU data:

browsertime/lib/firefox/webdriver/firefox.js

Lines 215 to 225 in 3daa78c

	let powerusage = await runner.runPrivilegedScript(`
	return new Promise(async function(resolve) {
	Services.fog.initializeFOG(); // prevents timeout when collecting CPU metrics
	await Services.fog.testFlushAllChildren(); // force data from child processes to be sent to the parent.
	resolve(Glean.power.totalCpuTimeMs.testGetValue());
	});
	`);
	if (powerusage) {
	log.info('CPU / Power usage: ' + powerusage);
	}
	result.cpu = powerusage;

Maybe the log output needs to be reworded to only mention that it's CPU usage?

[soulgalore]

Let me check that, I think I reworded issue wrong. I think we always use root on Android when we test using Firefox and I was thinking we needed root to get that metric but I was wrong. Let me test again next week see what's going on.