Update from https://crrev.com/309717

sandbox/linux/seccomp-bpf/trap.h

Index: sandbox/linux/seccomp-bpf/trap.h
diff --git a/sandbox/linux/seccomp-bpf/trap.h b/sandbox/linux/seccomp-bpf/trap.h
index 0a184e6b6ac6752455d0a9abc0570c88cfc1e338..fea0052ffcd3e35226f5420abc1f6e97ee07db37 100644
--- a/sandbox/linux/seccomp-bpf/trap.h
+++ b/sandbox/linux/seccomp-bpf/trap.h
@@ -26,9 +26,9 @@ namespace sandbox {
 //   true. Threads are incompatible with the seccomp sandbox anyway.
 class SANDBOX_EXPORT Trap : public bpf_dsl::TrapRegistry {
  public:
-  virtual uint16_t Add(TrapFnc fnc, const void* aux, bool safe) override;
+  uint16_t Add(TrapFnc fnc, const void* aux, bool safe) override;
 
-  virtual bool EnableUnsafeTraps() override;
+  bool EnableUnsafeTraps() override;
 
   // Registry returns the trap registry used by Trap's SIGSYS handler,
   // creating it if necessary.