src: add missing namespace using statements in node_watchdog.h

Although these `using`s can derived from other header files, it will
be better to be self-contained.

PR-URL: #32117
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>

src/node_watchdog.cc

@@ -34,6 +34,7 @@ namespace node {
 using v8::Context;
 using v8::FunctionCallbackInfo;
 using v8::FunctionTemplate;
+using v8::Local;
 using v8::Object;
 using v8::Value;
 

src/node_watchdog.h

@@ -83,10 +83,10 @@ class SigintWatchdog : public SigintWatchdogBase {
 
 class TraceSigintWatchdog : public HandleWrap, public SigintWatchdogBase {
  public:
-  static void Init(Environment* env, Local<v8::Object> target);
+  static void Init(Environment* env, v8::Local<v8::Object> target);
   static void New(const v8::FunctionCallbackInfo<v8::Value>& args);
-  static void Start(const v8::FunctionCallbackInfo<Value>& args);
-  static void Stop(const v8::FunctionCallbackInfo<Value>& args);
+  static void Start(const v8::FunctionCallbackInfo<v8::Value>& args);
+  static void Stop(const v8::FunctionCallbackInfo<v8::Value>& args);
 
   SignalPropagation HandleSigint() override;
 
@@ -99,7 +99,7 @@ class TraceSigintWatchdog : public HandleWrap, public SigintWatchdogBase {
  private:
   enum class SignalFlags { None, FromIdle, FromInterrupt };
 
-  TraceSigintWatchdog(Environment* env, Local<v8::Object> object);
+  TraceSigintWatchdog(Environment* env, v8::Local<v8::Object> object);
   void HandleInterrupt();
 
   bool interrupting = false;