src: use global SealHandleScope

Helps to find Handle leaks in Debug mode.

Ref: a5244d3 "deps: backport 1f8555 from v8's upstream"

PR-URL: nodejs/node#3945
Reviewed-By: Fedor Indutny <fedor@indutny.com>
Reviewed-By: James Snell <jasnell@gmail.com>

src/node.cc

@@ -116,6 +116,7 @@ using v8::Number;
 using v8::Object;
 using v8::ObjectTemplate;
 using v8::PropertyCallbackInfo;
+using v8::SealHandleScope;
 using v8::String;
 using v8::TryCatch;
 using v8::Uint32;
@@ -3769,19 +3770,23 @@ int Start(int argc, char** argv) {
     if (use_debug_agent)
       EnableDebug(env);
 
-    bool more;
-    do {
-      more = uv_run(env->event_loop(), UV_RUN_ONCE);
-      if (more == false) {
-        EmitBeforeExit(env);
-
-        // Emit `beforeExit` if the loop became alive either after emitting
-        // event, or after running some callbacks.
-        more = uv_loop_alive(env->event_loop());
-        if (uv_run(env->event_loop(), UV_RUN_NOWAIT) != 0)
-          more = true;
-      }
-    } while (more == true);
+    {
+      SealHandleScope seal(node_isolate);
+      bool more;
+      do {
+        more = uv_run(env->event_loop(), UV_RUN_ONCE);
+        if (more == false) {
+          EmitBeforeExit(env);
+
+          // Emit `beforeExit` if the loop became alive either after emitting
+          // event, or after running some callbacks.
+          more = uv_loop_alive(env->event_loop());
+          if (uv_run(env->event_loop(), UV_RUN_NOWAIT) != 0)
+            more = true;
+        }
+      } while (more == true);
+    }
+
     code = EmitExit(env);
     RunAtExit(env);