Add NetworkProperties to DataConnection.

Since we have NetworkProperties we can remove the individual accessors
from Phone and its subclasses.

Change-Id: Id9969a880405900a63051b3ae4019d889afb1fe8

core/java/android/net/ProxyProperties.java

@@ -57,6 +57,14 @@ public class ProxyProperties implements Parcelable {
         mExclusionList = exclusionList;
     }
 
+    @Override
+    public String toString() {
+        StringBuilder sb = new StringBuilder();
+        sb.append(mProxy.getHostAddress()).append(":").append(mPort)
+          .append(" xl=").append(mExclusionList);
+        return sb.toString();
+    }
+
     /**
      * Implement the Parcelable interface
      * @hide