Add basic logging infrastructure for bugreports

Test: as follows
    - built, flashed, booted
    - "adb shell dumpsys netd" shows logs
    - tests/runtests.sh passes
Change-Id: I0e44da7f9a9cc53074ffc396b958e9e2dbcd2603
diff --git a/server/Controllers.h b/server/Controllers.h
index 38ffade..ac17ef2 100644
--- a/server/Controllers.h
+++ b/server/Controllers.h
@@ -30,17 +30,18 @@
 #include "PppController.h"
 #include "ResolverController.h"
 #include "StrictController.h"
+#include "TcpSocketMonitor.h"
 #include "TetherController.h"
 #include "TrafficController.h"
 #include "WakeupController.h"
 #include "XfrmController.h"
-#include "TcpSocketMonitor.h"
+#include "netdutils/Log.h"
 
 namespace android {
 namespace net {
 
 class Controllers {
-public:
+  public:
     Controllers();
 
     NetworkController netCtrl;
@@ -61,7 +62,7 @@
 
     void init();
 
-private:
+  private:
     friend class ControllersTest;
     void initIptablesRules();
     static void initChildChains();
@@ -74,6 +75,7 @@
     static int (*execIptablesRestoreWithOutput)(IptablesTarget, const std::string&, std::string *);
 };
 
+extern netdutils::Log gLog;
 extern Controllers* gCtls;
 
 }  // namespace net