Added a new Verifier class to the BPF compiler.

sandbox/linux/seccomp-bpf/sandbox_bpf.h

Index: sandbox/linux/seccomp-bpf/sandbox_bpf.h
diff --git a/sandbox/linux/seccomp-bpf/sandbox_bpf.h b/sandbox/linux/seccomp-bpf/sandbox_bpf.h
index c3f504a32cdc7c8b9ab3dafecac7dc74f1b7e94c..395da826452ec35dc7d7a61e4d8bfd838859bce6 100644
--- a/sandbox/linux/seccomp-bpf/sandbox_bpf.h
+++ b/sandbox/linux/seccomp-bpf/sandbox_bpf.h
@@ -115,6 +115,7 @@ namespace playground2 {
 
 class Sandbox {
   friend class Util;
+  friend class Verifier;
 
  public:
   enum SandboxStatus {
@@ -153,6 +154,7 @@ class Sandbox {
   typedef ErrorCode (*EvaluateSyscall)(int sysno);
   typedef int       (*EvaluateArguments)(int sysno, int arg,
                                          Constraint *constraint);
+  typedef std::vector<std::pair<EvaluateSyscall,EvaluateArguments> >Evaluators;
 
   // There are a lot of reasons why the Seccomp sandbox might not be available.
   // This could be because the kernel does not support Seccomp mode, or it
@@ -235,8 +237,7 @@ class Sandbox {
   static bool          suppressLogging_;
   static SandboxStatus status_;
   static int           proc_fd_;
-  static std::vector<std::pair<EvaluateSyscall,
-                               EvaluateArguments> > evaluators_;
+  static Evaluators    evaluators_;
 };
 
 }  // namespace