Minor cleanup: IWYU, clang-tidy, etc.

PiperOrigin-RevId: 625836385
diff --git a/src/google/protobuf/has_bits.h b/src/google/protobuf/has_bits.h
index 93cda15..e0019e2 100644
--- a/src/google/protobuf/has_bits.h
+++ b/src/google/protobuf/has_bits.h
@@ -11,11 +11,9 @@
 #include <cassert>
 #include <cstddef>
 #include <cstdint>
+#include <cstring>
 #include <initializer_list>
 
-#include "google/protobuf/stubs/common.h"
-#include "google/protobuf/port.h"
-
 // Must be included last.
 #include "google/protobuf/port_def.inc"
 
diff --git a/src/google/protobuf/message_lite.cc b/src/google/protobuf/message_lite.cc
index 11dc247..103549e 100644
--- a/src/google/protobuf/message_lite.cc
+++ b/src/google/protobuf/message_lite.cc
@@ -20,8 +20,6 @@
 #include <string>
 #include <utility>
 
-#include "absl/base/dynamic_annotations.h"
-#include "absl/base/optimization.h"
 #include "absl/log/absl_check.h"
 #include "absl/log/absl_log.h"
 #include "absl/strings/cord.h"
@@ -29,14 +27,15 @@
 #include "absl/strings/internal/resize_uninitialized.h"
 #include "absl/strings/str_cat.h"
 #include "absl/strings/string_view.h"
-#include "absl/synchronization/mutex.h"
 #include "absl/types/optional.h"
+#include "absl/types/span.h"
 #include "google/protobuf/arena.h"
 #include "google/protobuf/generated_message_tctable_impl.h"
 #include "google/protobuf/io/coded_stream.h"
 #include "google/protobuf/io/zero_copy_stream.h"
 #include "google/protobuf/io/zero_copy_stream_impl.h"
 #include "google/protobuf/io/zero_copy_stream_impl_lite.h"
+#include "google/protobuf/metadata_lite.h"
 #include "google/protobuf/parse_context.h"
 
 
diff --git a/src/google/protobuf/message_lite.h b/src/google/protobuf/message_lite.h
index b47f407..1b85aa0 100644
--- a/src/google/protobuf/message_lite.h
+++ b/src/google/protobuf/message_lite.h
@@ -16,13 +16,13 @@
 #ifndef GOOGLE_PROTOBUF_MESSAGE_LITE_H__
 #define GOOGLE_PROTOBUF_MESSAGE_LITE_H__
 
-#include <atomic>
 #include <climits>
+#include <cstddef>
+#include <cstdint>
 #include <iosfwd>
 #include <string>
 
-#include "google/protobuf/stubs/common.h"
-#include "absl/base/call_once.h"
+#include "absl/base/attributes.h"
 #include "absl/log/absl_check.h"
 #include "absl/strings/cord.h"
 #include "absl/strings/string_view.h"
@@ -208,7 +208,7 @@
 // the internal library are allowed to create subclasses.
 class PROTOBUF_EXPORT MessageLite {
  public:
-  constexpr MessageLite() {}
+  constexpr MessageLite() = default;
   MessageLite(const MessageLite&) = delete;
   MessageLite& operator=(const MessageLite&) = delete;
   virtual ~MessageLite() = default;