Linux sandbox: cleanup sandbox-bpf naming.

sandbox/linux/seccomp-bpf/syscall.h

 // Copyright (c) 2012 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_SYSCALL_H__
 #define SANDBOX_LINUX_SECCOMP_BPF_SYSCALL_H__
 
 #include <stdint.h>
 
-namespace playground2 {
+namespace sandbox {
 
 // We have to make sure that we have a single "magic" return address for
 // our system calls, which we can check from within a BPF filter. This
 // works by writing a little bit of asm() code that a) enters the kernel, and
 // that also b) can be invoked in a way that computes this return address.
 // Passing "nr" as "-1" computes the "magic" return address. Passing any
 // other value invokes the appropriate system call.
 intptr_t SandboxSyscall(int nr,
                         intptr_t p0,
                         intptr_t p1,
@@ skipping 105 matching lines @@
   return SandboxSyscall(nr, p0, 0, 0, 0, 0, 0);
 }
 
 inline intptr_t SandboxSyscall(int nr) __attribute__((always_inline));
 inline intptr_t SandboxSyscall(int nr) {
   return SandboxSyscall(nr, 0, 0, 0, 0, 0, 0);
 }
 
 #endif  // Pre-C++11
 
-}  // namespace
+}  // namespace sandbox
 
 #endif  // SANDBOX_LINUX_SECCOMP_BPF_SYSCALL_H__