Large IWYU cleanup for seccomp-bpf

sandbox/linux/seccomp-bpf/codegen.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_CODEGEN_H__
 #define SANDBOX_LINUX_SECCOMP_BPF_CODEGEN_H__
 
 #include <map>
-#include <set>
 #include <vector>
 
-#include "sandbox/linux/seccomp-bpf/basicblock.h"
-#include "sandbox/linux/seccomp-bpf/instruction.h"
 #include "sandbox/linux/seccomp-bpf/sandbox_bpf.h"
 #include "sandbox/sandbox_export.h"
 
 namespace sandbox {
+struct BasicBlock;
+class ErrorCode;
+struct Instruction;
 
 typedef std::vector<Instruction*> Instructions;
 typedef std::vector<BasicBlock*> BasicBlocks;
 typedef std::map<const Instruction*, int> BranchTargets;
 typedef std::map<const Instruction*, BasicBlock*> TargetsToBlocks;
 typedef std::map<const BasicBlock*, int> IncomingBranches;
 
 // The code generator instantiates a basic compiler that can convert a
 // graph of BPF instructions into a well-formed stream of BPF instructions.
 // Most notably, it ensures that jumps are always forward and don't exceed
@@ skipping 123 matching lines @@
   BasicBlocks basic_blocks_;
 
   // Compile() must only ever be called once as it makes destructive changes
   // to the DAG.
   bool compiled_;
 };
 
 }  // namespace sandbox
 
 #endif  // SANDBOX_LINUX_SECCOMP_BPF_CODEGEN_H__