Move isAtLeastB to dependencies

So it is testable.

Test: TH
Change-Id: Ie63a3583c2e9d327cf47effc2c9352e2da03c7c0
diff --git a/service-t/src/com/android/server/ethernet/EthernetTracker.java b/service-t/src/com/android/server/ethernet/EthernetTracker.java
index 53a899e..1c453cb 100644
--- a/service-t/src/com/android/server/ethernet/EthernetTracker.java
+++ b/service-t/src/com/android/server/ethernet/EthernetTracker.java
@@ -170,6 +170,10 @@
             return resources.get().getStringArray(
                     com.android.connectivity.resources.R.array.config_ethernet_interfaces);
         }
+
+        public boolean isAtLeastB() {
+            return SdkLevel.isAtLeastB();
+        }
     }
 
     private class EthernetNetlinkMonitor extends NetlinkMonitor {
@@ -770,7 +774,7 @@
         // capabilities) to prevent certain Ethernet interfaces from becoming
         // the default network. To avoid breaking existing device configurations, this
         // change is gated by the SDK level.
-        if (SdkLevel.isAtLeastB() && config.mCaps.isEmpty()) {
+        if (mDeps.isAtLeastB() && config.mCaps.isEmpty()) {
             nc = createDefaultNetworkCapabilities(false /* isTestIface */, config.mTransport);
         } else {
             nc = createNetworkCapabilities(config.mCaps, config.mTransport).build();