Add new network capabilities to support automotive head unit via USB

- Add a new transport type for USB and a new network capability
to support automotive head unit.
- In order to pass DnsManagerTest#testTransportTypesEqual, Android.bp
needs to link to dnsresolver_aidl_interface-V8-java. That test checks
whether the TRANSPORT types defined in NetworkCapabilities are the
same as IDnsResolver.aidl.

(clean cherry-pick of change in downstream branch history, original
change ID before project move:
Iec2df09a776d779108f95098e01b7ffdf6f8867a)

Bug: 181742019
Test: atest FrameworksNetTests

Merged-In: I3c2563d4ae4e3715d0c6270344ba8f7ef067872f
Change-Id: Ie438ec68577ebdaaf990795fa27f1169b0105411
diff --git a/framework/api/current.txt b/framework/api/current.txt
index 7692e30..715a532 100644
--- a/framework/api/current.txt
+++ b/framework/api/current.txt
@@ -310,6 +310,7 @@
     field public static final int NET_CAPABILITY_ENTERPRISE = 29; // 0x1d
     field public static final int NET_CAPABILITY_FOREGROUND = 19; // 0x13
     field public static final int NET_CAPABILITY_FOTA = 3; // 0x3
+    field public static final int NET_CAPABILITY_HEAD_UNIT = 32; // 0x20
     field public static final int NET_CAPABILITY_IA = 7; // 0x7
     field public static final int NET_CAPABILITY_IMS = 4; // 0x4
     field public static final int NET_CAPABILITY_INTERNET = 12; // 0xc
@@ -333,6 +334,7 @@
     field public static final int TRANSPORT_CELLULAR = 0; // 0x0
     field public static final int TRANSPORT_ETHERNET = 3; // 0x3
     field public static final int TRANSPORT_LOWPAN = 6; // 0x6
+    field public static final int TRANSPORT_USB = 8; // 0x8
     field public static final int TRANSPORT_VPN = 4; // 0x4
     field public static final int TRANSPORT_WIFI = 1; // 0x1
     field public static final int TRANSPORT_WIFI_AWARE = 5; // 0x5