Move ForkWithFlags from sandbox/ to base/ and plug it into LaunchProcess.

sandbox/linux/services/syscall_wrappers_unittest.cc

 // Copyright 2014 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.
 
 #include "sandbox/linux/services/syscall_wrappers.h"
 
 #include <sys/syscall.h>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <unistd.h>
@@ skipping 42 matching lines @@
     _exit(1);
   }
 
   ASSERT_NE(-1, pid);
   int status = 0;
   ASSERT_EQ(pid, HANDLE_EINTR(waitpid(pid, &status, 0)));
   ASSERT_TRUE(WIFEXITED(status));
   EXPECT_EQ(kSuccessExit, WEXITSTATUS(status));
 }
 
-TEST(SyscallWrappers, ForkWithFlagsUpdatesPidCache) {
-  // The libc clone function, which allows ForkWithFlags to keep the pid cache
-  // up to date, does not work on Valgrind.
-  if (IsRunningOnValgrind()) {
-    return;
-  }
-
-  // Warm up the libc pid cache, if there is one.
-  ASSERT_EQ(sys_getpid(), getpid());
-
-  pid_t ctid = 0;
-  pid_t pid = ForkWithFlags(CLONE_CHILD_SETTID | SIGCHLD, nullptr, &ctid);
-
-  const int kSuccessExit = 0;
-  if (0 == pid) {
-    // In child.  Check both the raw getpid syscall and the libc getpid wrapper
-    // (which may rely on a pid cache).
-    if (sys_getpid() == ctid && getpid() == ctid)
-      _exit(kSuccessExit);
-    _exit(1);
-  }
-
-  ASSERT_NE(-1, pid);
-  int status = 0;
-  ASSERT_EQ(pid, HANDLE_EINTR(waitpid(pid, &status, 0)));
-  ASSERT_TRUE(WIFEXITED(status));
-  EXPECT_EQ(kSuccessExit, WEXITSTATUS(status));
-}
-
 }  // namespace
 
 }  // namespace sandbox