sandbox_bpf: Remove Traverse method.

All calls to this were removed in
https://codereview.chromium.org/628823003/.

BUG=414363

Review URL: https://codereview.chromium.org/652123002

Cr-Commit-Position: refs/heads/master@{#299436}

sandbox/linux/seccomp-bpf/codegen.cc

@@ -14,31 +14,6 @@
 #include "sandbox/linux/seccomp-bpf/instruction.h"
 #include "sandbox/linux/seccomp-bpf/linux_seccomp.h"
 
-namespace {
-
-// Helper function for Traverse().
-void TraverseRecursively(std::set<sandbox::Instruction*>* visited,
-                         sandbox::Instruction* instruction) {
-  if (visited->find(instruction) == visited->end()) {
-    visited->insert(instruction);
-    switch (BPF_CLASS(instruction->code)) {
-      case BPF_JMP:
-        if (BPF_OP(instruction->code) != BPF_JA) {
-          TraverseRecursively(visited, instruction->jf_ptr);
-        }
-        TraverseRecursively(visited, instruction->jt_ptr);
-        break;
-      case BPF_RET:
-        break;
-      default:
-        TraverseRecursively(visited, instruction->next);
-        break;
-    }
-  }
-}
-
-}  // namespace
-
 namespace sandbox {
 
 CodeGen::CodeGen() : compiled_(false) {}
@@ -189,18 +164,6 @@ Instruction* CodeGen::MakeInstruction(uint16_t code,
   return insn;
 }
 
-void CodeGen::Traverse(Instruction* instruction,
-                       void (*fnc)(Instruction*, void*),
-                       void* aux) {
-  std::set<Instruction*> visited;
-  TraverseRecursively(&visited, instruction);
-  for (std::set<Instruction*>::const_iterator iter = visited.begin();
-       iter != visited.end();
-       ++iter) {
-    fnc(*iter, aux);
-  }
-}
-
 void CodeGen::FindBranchTargets(const Instruction& instructions,
                                 BranchTargets* branch_targets) {
   // Follow all possible paths through the "instructions" graph and compute

sandbox/linux/seccomp-bpf/codegen.h

@@ -72,14 +72,6 @@ class SANDBOX_EXPORT CodeGen {
                                Instruction* jt,
                                Instruction* jf);
 
-  // Traverse the graph of instructions and visit each instruction once.
-  // Traversal order is implementation-defined. It is acceptable to make
-  // changes to the graph from within the callback function. These changes
-  // do not affect traversal.
-  // The "fnc" function gets called with both the instruction and the opaque
-  // "aux" pointer.
-  void Traverse(Instruction*, void (*fnc)(Instruction*, void* aux), void* aux);
-
   // Compiles the graph of instructions into a BPF program that can be passed
   // to the kernel. Please note that this function modifies the graph in place
   // and must therefore only be called once per graph.