Revert "Allow SIGQUIT to toggle the vm-service server a la command line Dart. (#3857)" (#3859)

This reverts commit d67b614a.

Fuchsia TO-370

runtime/dart_init.cc

@@ -195,16 +195,15 @@ Dart_Isolate ServiceIsolateCreateCallback(const char* script_uri,
     DartUI::InitForIsolate();
     DartRuntimeHooks::Install(DartRuntimeHooks::SecondaryIsolate, script_uri);
     const Settings& settings = Settings::Get();
-    std::string ip = settings.ipv6 ? "::1" : "127.0.0.1";
-    intptr_t port = -1;
     if (settings.enable_observatory) {
-      port = settings.observatory_port;
+      std::string ip = settings.ipv6 ? "::1" : "127.0.0.1";
+      const intptr_t port = settings.observatory_port;
+      const bool disable_websocket_origin_check = false;
+      const bool service_isolate_booted = DartServiceIsolate::Startup(
+          ip, port, tonic::DartState::HandleLibraryTag,
+          IsRunningPrecompiledCode(), disable_websocket_origin_check, error);
+      FTL_CHECK(service_isolate_booted) << error;
     }
-    const bool disable_websocket_origin_check = false;
-    const bool service_isolate_booted = DartServiceIsolate::Startup(
-        ip, port, tonic::DartState::HandleLibraryTag,
-        IsRunningPrecompiledCode(), disable_websocket_origin_check, error);
-    FTL_CHECK(service_isolate_booted) << error;
 
     if (g_service_isolate_hook)
       g_service_isolate_hook(IsRunningPrecompiledCode());

runtime/dart_service_isolate.cc

@@ -160,7 +160,7 @@ bool DartServiceIsolate::Startup(std::string server_ip,
     // port when the HTTP server is started.
     server_port = 0;
   }
-  // Set the HTTP server's port.
+  // Set the HTTP's servers port.
   result = Dart_SetField(library, Dart_NewStringFromCString("_port"),
                          Dart_NewInteger(server_port));
   SHUTDOWN_ON_ERROR(result);
@@ -171,22 +171,6 @@ bool DartServiceIsolate::Startup(std::string server_ip,
       Dart_SetField(library, Dart_NewStringFromCString("_originCheckDisabled"),
                     Dart_NewBoolean(disable_origin_check));
   SHUTDOWN_ON_ERROR(result);
-
-  // Get _getWatchSignalInternal from dart:io.
-  Dart_Handle dart_io_str = Dart_NewStringFromCString("dart:io");
-  SHUTDOWN_ON_ERROR(dart_io_str);
-  Dart_Handle io_lib = Dart_LookupLibrary(dart_io_str);
-  SHUTDOWN_ON_ERROR(io_lib);
-  Dart_Handle function_name =
-      Dart_NewStringFromCString("_getWatchSignalInternal");
-  SHUTDOWN_ON_ERROR(function_name);
-  Dart_Handle signal_watch = Dart_Invoke(io_lib, function_name, 0, NULL);
-  SHUTDOWN_ON_ERROR(signal_watch);
-  Dart_Handle field_name = Dart_NewStringFromCString("_signalWatch");
-  SHUTDOWN_ON_ERROR(field_name);
-  result = Dart_SetField(library, field_name, signal_watch);
-  SHUTDOWN_ON_ERROR(field_name);
-
   return true;
 }