Fix build breakage encountered by Flutter

runtime/bin/process.cc

 // Copyright (c) 2013, 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/dartutils.h"
 #include "bin/dbg_connection.h"
 #include "bin/eventhandler.h"
 #include "bin/io_buffer.h"
 #include "bin/log.h"
 #include "bin/platform.h"
@@ skipping 244 matching lines @@
   // Ignore result if passing invalid argument and just exit 0.
   DartUtils::GetInt64Value(Dart_GetNativeArgument(args, 0), &status);
   Dart_ShutdownIsolate();
   Process::TerminateExitCodeHandler();
   char* error = Dart_Cleanup();
   if (error != NULL) {
     Log::PrintErr("VM cleanup failed: %s\n", error);
     free(error);
   }
   if (do_vm_shutdown) {
+#ifdef LEGACY_DEBUG_PROTOCOL_ENABLED
+    // Note that this dependency crosses logical project boundaries by making
+    // the dart:io implementation depend upon the standalone VM's legacy debug
+    // protocol. This breaks projects which want to use our dart:io
+    // implementation. Because the protocol is going away shortly, it's
+    // reasonable to leave it behind a #ifdef that is only enabled for the
+    // standalone VM for now.
     DebuggerConnectionHandler::StopHandler();
+#endif
     EventHandler::Stop();
   }
   exit(static_cast<int>(status));
 }
 
 
 void FUNCTION_NAME(Process_SetExitCode)(Dart_NativeArguments args) {
   int64_t status = 0;
   // Ignore result if passing invalid argument and just set exit code to 0.
   DartUtils::GetInt64Value(Dart_GetNativeArgument(args, 0), &status);
@@ skipping 107 matching lines @@
     free(const_cast<char*>(system_string));
     Dart_PropagateError(result);
   }
   memmove(buffer, system_string, system_len);
   free(const_cast<char*>(system_string));
   Dart_SetReturnValue(args, external_array);
 }
 
 }  // namespace bin
 }  // namespace dart