Remove `include/grpcpp/impl/codegen/security/auth_context.h` (#31292)

diff --git a/doc/server_side_auth.md b/doc/server_side_auth.md
index b4231fd..8842902 100644
--- a/doc/server_side_auth.md
+++ b/doc/server_side_auth.md
@@ -12,7 +12,7 @@
 
 The contents of the *auth properties* are populated by an *auth interceptor*. The interceptor also chooses which property key will act as the peer identity (e.g. for client certificate authentication this property will be `"x509_common_name"` or `"x509_subject_alternative_name"`).
 
-Note that AuthContext is generally not modifiable, except when used via an AuthMetadataProcessor([reference](https://github.com/grpc/grpc/blob/master/include/grpcpp/impl/codegen/security/auth_context.h)). 
+Note that AuthContext is generally not modifiable, except when used via an AuthMetadataProcessor([reference](https://github.com/grpc/grpc/blob/master/include/grpcpp/security/auth_context.h)).
 However, because the AuthContext is a connection-level object, when it is modified via an AuthMetadataProcessor, the modifications will be visible on all subsequent calls on the same connection.
 
 WARNING: AuthContext is the only reliable source of truth when it comes to authenticating RPCs. Using any other call/context properties for authentication purposes is wrong and inherently unsafe.
diff --git a/include/grpcpp/impl/codegen/security/auth_context.h b/include/grpcpp/impl/codegen/security/auth_context.h
index c67e1cf..7fd7ca1 100644
--- a/include/grpcpp/impl/codegen/security/auth_context.h
+++ b/include/grpcpp/impl/codegen/security/auth_context.h
@@ -19,83 +19,9 @@
 #ifndef GRPCPP_IMPL_CODEGEN_SECURITY_AUTH_CONTEXT_H
 #define GRPCPP_IMPL_CODEGEN_SECURITY_AUTH_CONTEXT_H
 
-// IWYU pragma: private, include <grpcpp/security/auth_context.h>
+// IWYU pragma: private
 
-#include <iterator>
-#include <vector>
-
-#include <grpcpp/impl/codegen/config.h>
-#include <grpcpp/impl/codegen/string_ref.h>
-
-struct grpc_auth_context;
-struct grpc_auth_property;
-struct grpc_auth_property_iterator;
-
-namespace grpc {
-class SecureAuthContext;
-
-typedef std::pair<string_ref, string_ref> AuthProperty;
-
-class AuthPropertyIterator {
- public:
-  using iterator_category = std::forward_iterator_tag;
-  using value_type = const AuthProperty;
-  using pointer = void;
-  using reference = void;
-  using difference_type = std::ptrdiff_t;
-
-  ~AuthPropertyIterator();
-  AuthPropertyIterator& operator++();
-  AuthPropertyIterator operator++(int);
-  bool operator==(const AuthPropertyIterator& rhs) const;
-  bool operator!=(const AuthPropertyIterator& rhs) const;
-  AuthProperty operator*();
-
- protected:
-  AuthPropertyIterator();
-  AuthPropertyIterator(const grpc_auth_property* property,
-                       const grpc_auth_property_iterator* iter);
-
- private:
-  friend class SecureAuthContext;
-  const grpc_auth_property* property_;
-  // The following items form a grpc_auth_property_iterator.
-  const grpc_auth_context* ctx_;
-  size_t index_;
-  const char* name_;
-};
-
-/// Class encapsulating the Authentication Information.
-///
-/// It includes the secure identity of the peer, the type of secure transport
-/// used as well as any other properties required by the authorization layer.
-class AuthContext {
- public:
-  virtual ~AuthContext() {}
-
-  /// Returns true if the peer is authenticated.
-  virtual bool IsPeerAuthenticated() const = 0;
-
-  /// A peer identity.
-  ///
-  /// It is, in general, comprised of one or more properties (in which case they
-  /// have the same name).
-  virtual std::vector<grpc::string_ref> GetPeerIdentity() const = 0;
-  virtual std::string GetPeerIdentityPropertyName() const = 0;
-
-  /// Returns all the property values with the given name.
-  virtual std::vector<grpc::string_ref> FindPropertyValues(
-      const std::string& name) const = 0;
-
-  /// Iteration over all the properties.
-  virtual AuthPropertyIterator begin() const = 0;
-  virtual AuthPropertyIterator end() const = 0;
-
-  /// Mutation functions: should only be used by an AuthMetadataProcessor.
-  virtual void AddProperty(const std::string& key, const string_ref& value) = 0;
-  virtual bool SetPeerIdentityPropertyName(const std::string& name) = 0;
-};
-
-}  // namespace grpc
+/// TODO(chengyuc): Remove this file after solving compatibility.
+#include <grpcpp/security/auth_context.h>
 
 #endif  // GRPCPP_IMPL_CODEGEN_SECURITY_AUTH_CONTEXT_H
diff --git a/include/grpcpp/security/auth_context.h b/include/grpcpp/security/auth_context.h
index 1778450..7253069 100644
--- a/include/grpcpp/security/auth_context.h
+++ b/include/grpcpp/security/auth_context.h
@@ -19,6 +19,81 @@
 #ifndef GRPCPP_SECURITY_AUTH_CONTEXT_H
 #define GRPCPP_SECURITY_AUTH_CONTEXT_H
 
-#include <grpcpp/impl/codegen/security/auth_context.h>  // IWYU pragma: export
+#include <iterator>
+#include <vector>
+
+#include <grpcpp/support/config.h>
+#include <grpcpp/support/string_ref.h>
+
+struct grpc_auth_context;
+struct grpc_auth_property;
+struct grpc_auth_property_iterator;
+
+namespace grpc {
+class SecureAuthContext;
+
+typedef std::pair<string_ref, string_ref> AuthProperty;
+
+class AuthPropertyIterator {
+ public:
+  using iterator_category = std::forward_iterator_tag;
+  using value_type = const AuthProperty;
+  using pointer = void;
+  using reference = void;
+  using difference_type = std::ptrdiff_t;
+
+  ~AuthPropertyIterator();
+  AuthPropertyIterator& operator++();
+  AuthPropertyIterator operator++(int);
+  bool operator==(const AuthPropertyIterator& rhs) const;
+  bool operator!=(const AuthPropertyIterator& rhs) const;
+  AuthProperty operator*();
+
+ protected:
+  AuthPropertyIterator();
+  AuthPropertyIterator(const grpc_auth_property* property,
+                       const grpc_auth_property_iterator* iter);
+
+ private:
+  friend class SecureAuthContext;
+  const grpc_auth_property* property_;
+  // The following items form a grpc_auth_property_iterator.
+  const grpc_auth_context* ctx_;
+  size_t index_;
+  const char* name_;
+};
+
+/// Class encapsulating the Authentication Information.
+///
+/// It includes the secure identity of the peer, the type of secure transport
+/// used as well as any other properties required by the authorization layer.
+class AuthContext {
+ public:
+  virtual ~AuthContext() {}
+
+  /// Returns true if the peer is authenticated.
+  virtual bool IsPeerAuthenticated() const = 0;
+
+  /// A peer identity.
+  ///
+  /// It is, in general, comprised of one or more properties (in which case they
+  /// have the same name).
+  virtual std::vector<grpc::string_ref> GetPeerIdentity() const = 0;
+  virtual std::string GetPeerIdentityPropertyName() const = 0;
+
+  /// Returns all the property values with the given name.
+  virtual std::vector<grpc::string_ref> FindPropertyValues(
+      const std::string& name) const = 0;
+
+  /// Iteration over all the properties.
+  virtual AuthPropertyIterator begin() const = 0;
+  virtual AuthPropertyIterator end() const = 0;
+
+  /// Mutation functions: should only be used by an AuthMetadataProcessor.
+  virtual void AddProperty(const std::string& key, const string_ref& value) = 0;
+  virtual bool SetPeerIdentityPropertyName(const std::string& name) = 0;
+};
+
+}  // namespace grpc
 
 #endif  // GRPCPP_SECURITY_AUTH_CONTEXT_H