Add SetCapabilities for setting capabilities to an exact set.

sandbox/linux/services/syscall_wrappers.cc

Index: sandbox/linux/services/syscall_wrappers.cc
diff --git a/sandbox/linux/services/syscall_wrappers.cc b/sandbox/linux/services/syscall_wrappers.cc
index af9dc462f861fa99e7e8b11909bc237e9a8e8a30..5a4045b4d2c4b786c882bd09c1bee885d9446f0d 100644
--- a/sandbox/linux/services/syscall_wrappers.cc
+++ b/sandbox/linux/services/syscall_wrappers.cc
@@ -77,4 +77,12 @@ int sys_prlimit64(pid_t pid,
   return syscall(__NR_prlimit64, pid, resource, new_limit, old_limit);
 }
 
+int sys_capget(cap_hdr* hdrp, cap_data* datap) {
+  return syscall(__NR_capget, hdrp, datap);
+}
+
+int sys_capset(cap_hdr* hdrp, const cap_data* datap) {
+  return syscall(__NR_capset, hdrp, datap);
+}
+
 }  // namespace sandbox