Added ctrl-\ command that dumps isolate stacks to dart binary.

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_debugger_api.h"
@@ skipping 733 matching lines @@
     return kErrorExitCode;  // Indicates we encountered an error.
   }
   delete [] isolate_name;
 
   Dart_Isolate isolate = Dart_CurrentIsolate();
   ASSERT(isolate != NULL);
   Dart_Handle result;
 
   Dart_EnterScope();
 
-  if (vmstats_port >= 0) {
-    VmStats::Start(vmstats_port, vmstats_root);
-  }
+  VmStats::Start(vmstats_port, vmstats_root);
 
   if (generate_script_snapshot) {
     // First create a snapshot.
     Dart_Handle result;
     uint8_t* buffer = NULL;
     intptr_t size = 0;
     result = Dart_CreateScriptSnapshot(&buffer, &size);
     if (Dart_IsError(result)) {
       Log::PrintErr("%s\n", Dart_GetError(result));
       Dart_ExitScope();
@@ skipping 64 matching lines @@
   Dart_ShutdownIsolate();
   // Terminate process exit-code handler.
   Process::TerminateExitCodeHandler();
   // Free copied argument strings if converted.
   if (argv_converted) {
     for (int i = 0; i < argc; i++) free(argv[i]);
   }
 
   return Process::GlobalExitCode();
 }