adding multitouch extension

[fernando-80]

Closes #27

The following tasks have been completed:

• Modified Web platform tests (link to pull request)

Implementation commitment:

• WebKit (https://bugs.webkit.org/show_bug.cgi?id=)
• Chromium (https://crbug.com/1143942)
• Gecko (https://bugzilla.mozilla.org/show_bug.cgi?id=1523351) - behind a couple of prefs.

[fernando-80]

@nondebug this is the multitouch extension spec
@knyg

[marcoscaceres]

Why not just an empty array?

[fernando-80]

Hi @marcoscaceres we thought about representing the absent surfaceDimensions with "null". Would there be any advantages to use the empty array instead? thanks~

[marcoscaceres]

@fernando-80, just wondering, are you affiliated with a W3C/WebAppsWG member company?

[marcoscaceres]

Another thing I thought of, there might be some overlap with the exciting Touch Events spec. It might be worth checking if there anything we could reuse from that... maybe not, but just might be worth exploring.

[fernando-80]

@fernando-80, just wondering, are you affiliated with a W3C/WebAppsWG member company?

Hi @marcoscaceres ! Nice to e-meet you! Thanks for your review! Yes, I report to Kelvin (@knyg) and I am Steve's (@sagoston) peer at Sony. We are working with Firefox and Matt/Chromium ( @nondebug ) implementing it.

[marcoscaceres]

Thanks @fernando-80! that's excellent to hear.

Ok, found it in Firefox:
https://searchfox.org/mozilla-central/source/dom/webidl/Gamepad.webidl#110

[marcoscaceres]

Checked WPT - we don't have any Web Platform Tests for this yet. Let's see if we can put together a list of possible tests from the spec text.