Safari 11 macOS and iOS intergation

[johache]

Safari 11 expected to land out of beta in Sept (both macOS and iOS). We should release our changes asap, so that users have a chance to update their site before the macOS/iOS official release.

Content of the PR:

• update of the webrtc-adapter submodule
• added the flag AdapterJS.options.forceSafariPlugin to force the use of the Temasys plugin on Safari 11+
• Moved the following variables into the AdapterJS scope: webrtcDetectedBrowser, webrtcDetectedVersion, webrtcMinimumVersion, webrtcDetectedType, webrtcDetectedDCSupport. We should deprecate their usage as global variables.
• AJS now relying on those to identify the browser being used

Safari 11 supports :

• gUM
• PeerConnection
• DataChannel

Known limitations of Safari Tech Preview and iOS 11

• No audiooutput in getSources/enumerateDevices
• No Screensharing support
• No DTMFSender support
• No RTCRecording support
• Connecting PeerConnections requires it to have a non empty stream (so gUM required) signalingState doesn't go to "close": https://bugs.webkit.org/show_bug.cgi?id=174314 This creates a weird situation where, if you want to use a DC on PC, you still have to gUM and attach the stream to the PC...
• No VP8 / VP9 support. H264 only. Means the free plugin cannot connect to Safari 11+ https://bugs.webkit.org/show_bug.cgi?id=173141

[oooookk7]

I'm good with that but should we test with webrtc/adapter 5.0.1 and consider bumping to that version? Seems like 5.0.0 has some MediaStream IDs mapping fixes.

[johache]

@letchoo indeed... They released those yesterday...

[oooookk7]

Actually are we using npm versioning instead of third_party for webrtc/adapter?

[johache]

Yes, indeed. I removed the submodule and replaced it with a node dep.