bpf_dsl: Move {Bool,Result}ExprImpl definition into separate header

sandbox/linux/bpf_dsl/bpf_dsl_impl.h

+// Copyright 2014 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_BPF_DSL_BPF_DSL_IMPL_H_
+#define SANDBOX_LINUX_BPF_DSL_BPF_DSL_IMPL_H_
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "sandbox/sandbox_export.h"
+
+namespace sandbox {
+class ErrorCode;
+class SandboxBPF;
+
+namespace bpf_dsl {
+namespace internal {
+
+// Internal interface implemented by BoolExpr implementations.
+class BoolExprImpl : public base::RefCounted<BoolExprImpl> {
+ public:
+  BoolExprImpl() {}
+  virtual ErrorCode Compile(SandboxBPF* sb,
+                            ErrorCode true_ec,
+                            ErrorCode false_ec) const = 0;
+
+ protected:
+  virtual ~BoolExprImpl() {}
+
+ private:
+  friend class base::RefCounted<BoolExprImpl>;
+  DISALLOW_COPY_AND_ASSIGN(BoolExprImpl);
+};
+
+// Internal interface implemented by ResultExpr implementations.
+class ResultExprImpl : public base::RefCounted<ResultExprImpl> {
+ public:
+  ResultExprImpl() {}
+  virtual ErrorCode Compile(SandboxBPF* sb) const = 0;
+  virtual bool HasUnsafeTraps() const;
+
+ protected:
+  virtual ~ResultExprImpl() {}
+
+ private:
+  friend class base::RefCounted<ResultExprImpl>;
+  DISALLOW_COPY_AND_ASSIGN(ResultExprImpl);
+};
+
+}  // namespace internal
+}  // namespace bpf_dsl
+}  // namespace sandbox
+
+#endif  // SANDBOX_LINUX_BPF_DSL_BPF_DSL_IMPL_H_