Move DumpWriter to libnetdutils

resolver related component in libnetd_resolv
needs it to easily print dump log.

Bug: 122564854
Test: built, flashed, booted
      system/netd/tests/runtests.sh pass
      adb shell dumpsys netd, worked fine

Change-Id: Ic97d5f21b738fc3074e9308f4846191e744ed479
diff --git a/server/ResolverController.h b/server/ResolverController.h
index 1a3b315..0c71be5 100644
--- a/server/ResolverController.h
+++ b/server/ResolverController.h
@@ -21,6 +21,7 @@
 #include <vector>
 
 #include "Dns64Configuration.h"
+#include "netdutils/DumpWriter.h"
 #include "netdutils/InternetAddresses.h"
 
 struct res_params;
@@ -28,7 +29,6 @@
 namespace android {
 namespace net {
 
-class DumpWriter;
 struct ResolverStats;
 
 class ResolverController {
@@ -71,7 +71,7 @@
 
     bool initResolver();
 
-    void dump(DumpWriter& dw, unsigned netId);
+    void dump(netdutils::DumpWriter& dw, unsigned netId);
 
   private:
     Dns64Configuration mDns64Configuration;