Add --observe to standalone embedder's help message.

runtime/bin/main.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 
 #include "include/dart_api.h"
 #include "include/dart_tools_api.h"
@@ skipping 749 matching lines @@
 "Common options:\n"
 "--checked or -c\n"
 "  Insert runtime type checks and enable assertions (checked mode).\n"
 "--help or -h\n"
 "  Display this message (add -v or --verbose for information about\n"
 "  all VM options).\n"
 "--package-root=<path> or -p<path>\n"
 "  Where to find packages, that is, \"package:...\" imports.\n"
 "--packages=<path>\n"
 "  Where to find a package spec file.\n"
+"--observe[=<port>[/<bind-address>]]\n"
+"  Enable the VM service and cause isolates to pause on exit (default port is\n"
+"  8181, default bind address is 127.0.0.1). With the default options,\n"
+"  Observatory will be available locally at http://127.0.0.1:8181/\n"
 "--version\n"
 "  Print the VM version.\n");
   } else {
     Log::PrintErr(
 "Supported options:\n"
 "--checked or -c\n"
 "  Insert runtime type checks and enable assertions (checked mode).\n"
 "--help or -h\n"
 "  Display this message (add -v or --verbose for information about\n"
 "  all VM options).\n"
 "--package-root=<path> or -p<path>\n"
 "  Where to find packages, that is, \"package:...\" imports.\n"
+"--packages=<path>\n"
+"  Where to find a package spec file.\n"
+"--observe[=<port>[/<bind-address>]]\n"
+"  Enable the VM service and cause isolates to pause on exit (default port is\n"
+"  8181, default bind address is 127.0.0.1). With the default options,\n"
+"  Observatory will be available locally at http://127.0.0.1:8181/\n"
 "--version\n"
 "  Print the VM version.\n"
 "\n"
 "--debug[:<port number>]\n"
 "  enables debugging and listens on specified port for debugger connections\n"
 "  (default port number is 5858)\n"
 "\n"
 "--break-at=<location>\n"
 "  sets a breakpoint at specified location where <location> is one of :\n"
 "  url:<line_num> e.g. test.dart:10\n"
@@ skipping 384 matching lines @@
   exit(Process::GlobalExitCode());
 }
 
 }  // namespace bin
 }  // namespace dart
 
 int main(int argc, char** argv) {
   dart::bin::main(argc, argv);
   UNREACHABLE();
 }