Determine the multipath hint from data usage.

Bug: 35142602
Test: builds, boots
Change-Id: I0f5de5e313ead442aa210f163db035fcf7de5e73

services/net/java/android/net/util/MultinetworkPolicyTracker.java

@@ -122,6 +122,7 @@ public class MultinetworkPolicyTracker {
         return mAvoidBadWifi;
     }
 
+    // TODO: move this to MultipathPolicyTracker.
     public int getMeteredMultipathPreference() {
         return mMeteredMultipathPreference;
     }