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/connection.cc b/connection.cc
index 43095ec..5d549a4 100644
--- a/connection.cc
+++ b/connection.cc
@@ -36,7 +36,7 @@
 }
 
 Connection::~Connection() {
-  VLOG(2) << __func__;
+  VLOG(2) << __func__ << " " << interface_name_;
 
   DCHECK(!routing_request_count_);
   routing_table_->FlushRoutes(interface_index_);
@@ -44,7 +44,7 @@
 }
 
 void Connection::UpdateFromIPConfig(const IPConfigRefPtr &config) {
-  VLOG(2) << __func__;
+  VLOG(2) << __func__ << " " << interface_name_;
 
   const IPConfig::Properties &properties = config->properties();
   IPAddress local(properties.address_family);
@@ -78,7 +78,9 @@
 }
 
 void Connection::SetIsDefault(bool is_default) {
-  VLOG(2) << __func__ << " " << is_default_ << " -> " << is_default;
+  VLOG(2) << __func__ << " "
+          << interface_name_ << " (index " << interface_index_ << ") "
+          << is_default_ << " -> " << is_default;
   if (is_default == is_default_) {
     return;
   }