Linux sandbox: cleanup sandbox-bpf naming.

sandbox/linux/seccomp-bpf-helpers/sigsys_handlers.h

 // Copyright (c) 2013 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_SECCOMP_BPF_HELPERS_SIGSYS_HANDLERS_H_
 #define SANDBOX_LINUX_SECCOMP_BPF_HELPERS_SIGSYS_HANDLERS_H_
 
 #include "base/basictypes.h"
 #include "build/build_config.h"
 
 // The handlers are suitable for use in Trap() error codes. They are
 // guaranteed to be async-signal safe.
 // See sandbox/linux/seccomp-bpf/trap.h to see how they work.
 
-namespace playground2 {
+namespace sandbox {
+
 struct arch_seccomp_data;
-}
-
-using playground2::arch_seccomp_data;
-
-namespace sandbox {
 
 // This handler will crash the currently running process. The crashing address
 // will be the number of the current system call, extracted from |args|.
 // This handler will also print to stderr the number of the crashing syscall.
 intptr_t CrashSIGSYS_Handler(const struct arch_seccomp_data& args, void* aux);
 
 // The following three handlers are suitable to report failures with the
 // clone(), prctl() and ioctl() system calls respectively.
 
 // The crashing address will be (clone_flags & 0xFFFFFF), where clone_flags is
 // the clone(2) argument, extracted from |args|.
 intptr_t SIGSYSCloneFailure(const struct arch_seccomp_data& args, void* aux);
 // The crashing address will be (option & 0xFFF), where option is the prctl(2)
 // argument.
 intptr_t SIGSYSPrctlFailure(const struct arch_seccomp_data& args, void* aux);
 // The crashing address will be request & 0xFFFF, where request is the ioctl(2)
 // argument.
 intptr_t SIGSYSIoctlFailure(const struct arch_seccomp_data& args, void* aux);
 
 }  // namespace sandbox.
 
 #endif  // SANDBOX_LINUX_SECCOMP_BPF_HELPERS_SIGSYS_HANDLERS_H_