Remove profiler signal handler on shutdown

runtime/vm/signal_handler_macos.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 "vm/globals.h"
 #include "vm/simulator.h"
 #include "vm/signal_handler.h"
 #if defined(TARGET_OS_MACOS)
 
 namespace dart {
@@ skipping 92 matching lines @@
   return lr;
 }
 
 
 void SignalHandler::Install(SignalAction action) {
   struct sigaction act;
   act.sa_handler = NULL;
   act.sa_sigaction = action;
   sigemptyset(&act.sa_mask);
   act.sa_flags = SA_RESTART | SA_SIGINFO;
-  // TODO(johnmccutchan): Do we care about restoring the signal handler?
-  struct sigaction old_act;
-  int r = sigaction(SIGPROF, &act, &old_act);
+  int r = sigaction(SIGPROF, &act, NULL);
   ASSERT(r == 0);
 }
 
+
+void SignalHandler::Remove() {
+  // Ignore future SIGPROF signals because by default SIGPROF will terminate
+  // the process and we may have some signals in flight.
+  struct sigaction act;
+  act.sa_handler = SIG_IGN;
+  sigemptyset(&act.sa_mask);
+  act.sa_flags = 0;
+  int r = sigaction(SIGPROF, &act, NULL);
+  ASSERT(r == 0);
+}
+
 
 }  // namespace dart
 
 #endif  // defined(TARGET_OS_MACOS)