Upgrade to Mapbox Streets source v8

[1ec5]

mapbox/mapbox-gl-native#13481 adds support for Mapbox Streets source v8, which is currently in beta. By the time map SDK v4.7.0 comes out, we’ll need to add corresponding support for Streets source v8; otherwise, anyone using a v8-dependent style will incur twice as much overhead from vector tile downloading and processing, while map labels and the current road name label will go blank. We’ll want to retain support for v7 for the time being, since some popular navigation styles still use v7.

Here are the changes we’ll need to make to accommodate both v7 and v8:

• Detect Streets source v8:

  mapbox-navigation-ios/MapboxNavigation/MGLVectorTileSource.swift

  Line 9 in dc9f1e9

  return configurationURL.scheme == "mapbox" && configurationURL.host!.components(separatedBy: ",").contains("mapbox.mapbox-streets-v7")

• Add Streets source v8 instead of v7 when Streets source is missing from the style:

  mapbox-navigation-ios/MapboxNavigation/RouteMapViewController.swift

  Lines 777 to 782 in 6bc02c3

  	// Add Mapbox Streets if the map does not already have it
  	if streetsSources.isEmpty {
  	let source = MGLVectorTileSource(identifier: "mapboxStreetsv7", configurationURL: URL(string: "mapbox://mapbox.mapbox-streets-v7")!)
  	style.addSource(source)
  	streetsSources.append(source)
  	}

• Use the road layer instead of road_label when the style contains Streets source v8:

  mapbox-navigation-ios/MapboxNavigation/NavigationMapView.swift

  Lines 1004 to 1005 in 6bc02c3

  	// Road labels should match road signage.
  	let locale = layer.sourceLayerIdentifier == "road_label" ? Locale(identifier: "mul") : nil

  mapbox-navigation-ios/MapboxNavigation/RouteMapViewController.swift

  Line 786 in 6bc02c3

  streetLabelLayer.sourceLayerIdentifier = "road_label"

/cc @mapbox/navigation-ios @mapbox/maps-ios @brsbl

[brsbl-zz]

Thanks for opening this ticket @1ec5. Do we need a similar one for android?