Revert "Signal handling."

runtime/bin/signal_blocker.h

 // 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.
 
 #ifndef BIN_SIGNAL_BLOCKER_H_
 #define BIN_SIGNAL_BLOCKER_H_
 
 #include "platform/globals.h"
 
 #if defined(TARGET_OS_WINDOWS)
 #error Do not include this file on Windows.
 #endif
 
 #include <signal.h>  // NOLINT
 
 #include "platform/thread.h"
 
 namespace dart {
 namespace bin {
 
 class ThreadSignalBlocker {
  public:
   explicit ThreadSignalBlocker(int sig) {
     sigset_t signal_mask;
     sigemptyset(&signal_mask);
     sigaddset(&signal_mask, sig);
     // Add sig to signal mask.
     int r = pthread_sigmask(SIG_BLOCK, &signal_mask, &old);
-    USE(r);
-    ASSERT(r == 0);
-  }
-
-  ThreadSignalBlocker(int sigs_count, const int sigs[]) {
-    sigset_t signal_mask;
-    sigemptyset(&signal_mask);
-    for (int i = 0; i < sigs_count; i++) {
-      sigaddset(&signal_mask, sigs[i]);
-    }
-    // Add sig to signal mask.
-    int r = pthread_sigmask(SIG_BLOCK, &signal_mask, &old);
-    USE(r);
     ASSERT(r == 0);
   }
 
   ~ThreadSignalBlocker() {
     // Restore signal mask.
     int r = pthread_sigmask(SIG_SETMASK, &old, NULL);
-    USE(r);
     ASSERT(r == 0);
   }
 
  private:
   sigset_t old;
 };
 
 
 #define TEMP_FAILURE_RETRY_BLOCK_SIGNALS(expression)                           \
     ({ ThreadSignalBlocker tsb(SIGPROF);                                       \
        int64_t __result;                                                       \
        do {                                                                    \
          __result = static_cast<int64_t>(expression);                          \
        } while (__result == -1L && errno == EINTR);                            \
        __result; })
 
 #define VOID_TEMP_FAILURE_RETRY_BLOCK_SIGNALS(expression)                      \
     (static_cast<void>(TEMP_FAILURE_RETRY_BLOCK_SIGNALS(expression)))
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // BIN_SIGNAL_BLOCKER_H_