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/TcpSocketMonitor.h b/server/TcpSocketMonitor.h
index 43c2c04..785f8ce 100644
--- a/server/TcpSocketMonitor.h
+++ b/server/TcpSocketMonitor.h
@@ -24,6 +24,7 @@
 #include <unordered_map>
 
 #include <android-base/thread_annotations.h>
+#include "netdutils/DumpWriter.h"
 #include "utils/String16.h"
 
 #include "Fwmark.h"
@@ -36,8 +37,6 @@
 
 using std::chrono::milliseconds;
 
-class DumpWriter;
-
 class TcpSocketMonitor {
   public:
     using time_point = std::chrono::time_point<std::chrono::steady_clock>;
@@ -78,7 +77,7 @@
     TcpSocketMonitor();
     ~TcpSocketMonitor();
 
-    void dump(DumpWriter& dw);
+    void dump(netdutils::DumpWriter& dw);
     void setPollingInterval(milliseconds duration);
     void resumePolling();
     void suspendPolling();