Revert of Remove SandboxBPF's dependency on CompatibilityPolicy

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 9bb414a61e6a98913973bfb1b3d4a8f4fb5558e4..923a9f3b1752535d45e966cdb9515cca0e394c2a 100644
--- a/sandbox/linux/seccomp-bpf/sandbox_bpf.h
+++ b/sandbox/linux/seccomp-bpf/sandbox_bpf.h
@@ -65,6 +65,14 @@
     PROCESS_MULTI_THREADED,   // The program may be multi-threaded.
   };
 
+  // When calling setSandboxPolicy(), the caller can provide an arbitrary
+  // pointer in |aux|. This pointer will then be forwarded to the sandbox
+  // policy each time a call is made through an EvaluateSyscall function
+  // pointer.  One common use case would be to pass the "aux" pointer as an
+  // argument to Trap() functions.
+  typedef ErrorCode (*EvaluateSyscall)(SandboxBPF* sandbox_compiler,
+                                       int system_call_number,
+                                       void* aux);
   // A vector of BPF instructions that need to be installed as a filter
   // program in the kernel.
   typedef std::vector<struct sock_filter> Program;
@@ -100,6 +108,20 @@
   // The sandbox becomes the new owner of this file descriptor and will
   // eventually close it when "StartSandbox()" executes.
   void set_proc_fd(int proc_fd);
+
+  // The system call evaluator function is called with the system
+  // call number. It can decide to allow the system call unconditionally
+  // by returning ERR_ALLOWED; it can deny the system call unconditionally by
+  // returning an appropriate "errno" value; or it can request inspection
+  // of system call argument(s) by returning a suitable ErrorCode.
+  // The "aux" parameter can be used to pass optional data to the system call
+  // evaluator. There are different possible uses for this data, but one of the
+  // use cases would be for the policy to then forward this pointer to a Trap()
+  // handler. In this case, of course, the data that is pointed to must remain
+  // valid for the entire time that Trap() handlers can be called; typically,
+  // this would be the lifetime of the program.
+  // DEPRECATED: use the policy interface below.
+  void SetSandboxPolicyDeprecated(EvaluateSyscall syscallEvaluator, void* aux);
 
   // Set the BPF policy as |policy|. Ownership of |policy| is transfered here
   // to the sandbox object.
@@ -207,7 +229,8 @@
   // policy. The caller has to make sure that "this" has not yet been
   // initialized with any other policies.
   bool RunFunctionInPolicy(void (*code_in_sandbox)(),
-                           scoped_ptr<SandboxBPFPolicy> policy);
+                           EvaluateSyscall syscall_evaluator,
+                           void* aux);
 
   // Performs a couple of sanity checks to verify that the kernel supports the
   // features that we need for successful sandboxing.