shill: Replace VLOG with SLOG.

This CL replaces all uses of VLOG(level) with SLOG(scope, level) with
the same verbose level and an appropriate scope for each affected
logging statement.

BUG=chromium-os:29641
TEST=Build and run unit tests. Test scope logging with ff_debug.

Change-Id: Ifdcf1faa2a309bcbd9ee369a66179ce9c7f1ad19
Reviewed-on: https://gerrit.chromium.org/gerrit/20629
Commit-Ready: Ben Chan <benchan@chromium.org>
Reviewed-by: Ben Chan <benchan@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
diff --git a/modem.cc b/modem.cc
index 8471397..112865c 100644
--- a/modem.cc
+++ b/modem.cc
@@ -11,6 +11,7 @@
 #include "shill/manager.h"
 #include "shill/proxy_factory.h"
 #include "shill/rtnl_handler.h"
+#include "shill/scope_logger.h"
 
 using base::Bind;
 using std::string;
@@ -57,7 +58,7 @@
 }
 
 void Modem::OnDeviceInfoAvailable(const string &link_name) {
-  VLOG(2) << __func__;
+  SLOG(Modem, 2) << __func__;
   if (pending_device_info_ && link_name_ == link_name) {
     // pending_device_info_ is only set if we've already been through
     // CreateDeviceFromModemProperties() and saved our initial
@@ -87,7 +88,7 @@
 
 void Modem::CreateDeviceFromModemProperties(
     const DBusPropertiesMap &modem_properties) {
-  VLOG(2) << __func__;
+  SLOG(Modem, 2) << __func__;
 
   if (device_.get()) {
     return;