Factor out snapshot helpers from main.cc.

runtime/bin/error_exit.cc

Index: runtime/bin/error_exit.cc
diff --git a/runtime/bin/error_exit.cc b/runtime/bin/error_exit.cc
new file mode 100644
index 0000000000000000000000000000000000000000..191a8e516894c6b155a8aba23593daa2ba38886f
--- /dev/null
+++ b/runtime/bin/error_exit.cc
@@ -0,0 +1,41 @@
+// Copyright (c) 2017, 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 "bin/error_exit.h"
+
+#include "bin/log.h"
+#include "bin/platform.h"
+#include "bin/process.h"
+#include "bin/eventhandler.h"
+#include "include/dart_api.h"
+#include "platform/assert.h"
+#include "platform/globals.h"
+
+namespace dart {
+namespace bin {
+
+void ErrorExit(int exit_code, const char* format, ...) {
+  va_list arguments;
+  va_start(arguments, format);
+  Log::VPrintErr(format, arguments);
+  va_end(arguments);
+
+  Dart_ExitScope();
+  Dart_ShutdownIsolate();
+
+  // Terminate process exit-code handler.
+  Process::TerminateExitCodeHandler();
+
+  char* error = Dart_Cleanup();
+  if (error != NULL) {
+    Log::PrintErr("VM cleanup failed: %s\n", error);
+    free(error);
+  }
+
+  EventHandler::Stop();
+  Platform::Exit(exit_code);
+}
+
+}  // namespace bin
+}  // namespace dart