lantern: data uris include server response time

[paulirish]

I noticed in the simulator that non-network URLs get treated, I believe, as actual network requests that will use a connection, etc.

Clearly there shouldn't be any server response time, though I think a non-zero RTT makes sense.. probably more like 5-10ms ish.

@patrickhulce can you help me think about how we'd fix this? Looking through the lantern code I'm not sure where we'd handle this case.

[patrickhulce]

Ooooo, yikes, yes let's fix that in simulateDownloadUntil! Check if it's a non-network protocol and have some constant/option for dealing with the RTT/server response time

lighthouse/lighthouse-core/lib/dependency-graph/simulator/tcp-connection.js

Lines 112 to 123 in d50ef9e

	/**
	* Simulates a network download of a particular number of bytes over an optional maximum amount of time
	* and returns information about the ending state.
	*
	* See https://hpbn.co/building-blocks-of-tcp/#three-way-handshake and
	* https://hpbn.co/transport-layer-security-tls/#tls-handshake for details.
	*
	* @param {number} bytesToDownload
	* @param {DownloadOptions} [options]
	* @return {DownloadResults}
	*/
	simulateDownloadUntil(bytesToDownload, options) {

[patrickhulce]

Given #9834 too we should probably do an audit of our network request usage for data URI mistakes and/or add more data URIs to our smokes :)