Add some missing includes

PiperOrigin-RevId: 589208816
diff --git a/src/google/protobuf/compiler/cpp/generator.cc b/src/google/protobuf/compiler/cpp/generator.cc
index 32d2a2c..ac0f982 100644
--- a/src/google/protobuf/compiler/cpp/generator.cc
+++ b/src/google/protobuf/compiler/cpp/generator.cc
@@ -17,15 +17,21 @@
 #include <utility>
 #include <vector>
 
+#include "absl/container/flat_hash_map.h"
+#include "absl/log/absl_check.h"
+#include "absl/memory/memory.h"
 #include "absl/status/status.h"
 #include "absl/strings/match.h"
 #include "absl/strings/str_cat.h"
+#include "absl/strings/str_split.h"
 #include "absl/strings/string_view.h"
 #include "google/protobuf/compiler/cpp/file.h"
 #include "google/protobuf/compiler/cpp/helpers.h"
+#include "google/protobuf/compiler/cpp/options.h"
 #include "google/protobuf/cpp_features.pb.h"
 #include "google/protobuf/descriptor.pb.h"
 #include "google/protobuf/descriptor_visitor.h"
+#include "google/protobuf/io/printer.h"
 
 
 namespace google {