Update from https://crrev.com/327068

sandbox/linux/system_headers/linux_signal.h

Index: sandbox/linux/system_headers/linux_signal.h
diff --git a/sandbox/linux/system_headers/linux_signal.h b/sandbox/linux/system_headers/linux_signal.h
new file mode 100644
index 0000000000000000000000000000000000000000..5db7fc5ea1dba01b659232c92c03b21a42380d6e
--- /dev/null
+++ b/sandbox/linux/system_headers/linux_signal.h
@@ -0,0 +1,73 @@
+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef SANDBOX_LINUX_SYSTEM_HEADERS_LINUX_SIGNAL_H_
+#define SANDBOX_LINUX_SYSTEM_HEADERS_LINUX_SIGNAL_H_
+
+// NOTE: On some toolchains, signal related ABI is incompatible with Linux's
+// (not undefined, but defined different values and in different memory
+// layouts). So, fill the gap here.
+
+#if defined(__native_client_nonsfi__)
+#if !defined(__i386__) && !defined(__arm__)
+#error "Unsupported platform"
+#endif
+
+#include <signal.h>
+
+#define LINUX_SIGBUS 7    // 10 in PNaCl toolchain.
+#define LINUX_SIGSEGV 11  // 11 in PNaCl toolchain. Defined for consistency.
+#define LINUX_SIGCHLD 17  // 20 in PNaCl toolchain.
+#define LINUX_SIGSYS 31   // 12 in PNaCl toolchain.
+
+#define LINUX_SIG_BLOCK 0    // 1 in PNaCl toolchain.
+#define LINUX_SIG_UNBLOCK 1  // 2 in PNaCl toolchain.
+
+#define LINUX_SA_SIGINFO 4           // 2 in PNaCl toolchain.
+#define LINUX_SA_NODEFER 0x40000000  // Undefined in PNaCl toolchain.
+#define LINUX_SA_RESTART 0x10000000  // Undefined in PNaCl toolchain.
+
+#define LINUX_SIG_DFL 0  // In PNaCl toolchain, unneeded cast is applied.
+
+struct LinuxSigInfo {
+  int si_signo;
+  int si_errno;
+  int si_code;
+
+  // Extra data is followed by the |si_code|. The length depends on the
+  // signal number.
+  char _sifields[1];
+};
+
+#include "sandbox/linux/system_headers/linux_ucontext.h"
+
+#else  // !defined(__native_client_nonsfi__)
+
+// Just alias the toolchain's value.
+#include <signal.h>
+
+#define LINUX_SIGBUS SIGBUS
+#define LINUX_SIGSEGV SIGSEGV
+#define LINUX_SIGCHLD SIGCHLD
+#define LINUX_SIGSYS SIGSYS
+
+#define LINUX_SIG_BLOCK SIG_BLOCK
+#define LINUX_SIG_UNBLOCK SIG_UNBLOCK
+
+#define LINUX_SA_SIGINFO SA_SIGINFO
+#define LINUX_SA_NODEFER SA_NODEFER
+#define LINUX_SA_RESTART SA_RESTART
+
+#define LINUX_SIG_DFL SIG_DFL
+
+typedef siginfo_t LinuxSigInfo;
+
+#if defined(__ANDROID__)
+// Android's signal.h doesn't define ucontext etc.
+#include "sandbox/linux/system_headers/linux_ucontext.h"
+#endif  // defined(__ANDROID__)
+
+#endif  // !defined(__native_client_nonsfi__)
+
+#endif  // SANDBOX_LINUX_SYSTEM_HEADERS_LINUX_SIGNAL_H_