shill: logging improvements (routing-related)

BUG=None
TEST=unit tests

Change-Id: I948017ae3ddc88f2c67dd80776f87887bbd3883b
Reviewed-on: https://gerrit.chromium.org/gerrit/16404
Commit-Ready: mukesh agrawal <quiche@chromium.org>
Reviewed-by: mukesh agrawal <quiche@chromium.org>
Tested-by: mukesh agrawal <quiche@chromium.org>
diff --git a/ip_address.cc b/ip_address.cc
index e71f574..d360aaa 100644
--- a/ip_address.cc
+++ b/ip_address.cc
@@ -70,7 +70,7 @@
   address_ = ByteString(GetAddressLength(family_));
 }
 
-bool IPAddress::ToString(string *address_string) const {
+bool IPAddress::IntoString(string *address_string) const {
   // Noting that INET6_ADDRSTRLEN > INET_ADDRSTRLEN
   char address_buf[INET6_ADDRSTRLEN];
   if (GetLength() != GetAddressLength(family_) ||
@@ -81,4 +81,10 @@
   return true;
 }
 
+string IPAddress::ToString() const {
+  string out("<unknown>");
+  IntoString(&out);
+  return out;
+}
+
 }  // namespace shill