Remove code for the paused linker-guided field stripping (go/lgpfs-paused).

PiperOrigin-RevId: 544763667

src/google/protobuf/compiler/cpp/helpers.h

@@ -396,10 +396,6 @@ bool ShouldSplit(const FieldDescriptor* field, const Options& options);
 bool ShouldForceAllocationOnConstruction(const Descriptor* desc,
                                          const Options& options);
 
-inline bool IsFieldUsed(const FieldDescriptor* /* field */, const Options&) {
-  return true;
-}
-
 // Does the file contain any definitions that need extension_set.h?
 bool HasExtensionsOrExtendableMessage(const FileDescriptor* file);
 

src/google/protobuf/compiler/cpp/message.cc

@@ -3999,12 +3999,6 @@ void MessageGenerator::GenerateSerializeWithCachedSizesBodyShuffled(
 
   std::vector<const FieldDescriptor*> ordered_fields =
       SortFieldsByNumber(descriptor_);
-  ordered_fields.erase(
-      std::remove_if(ordered_fields.begin(), ordered_fields.end(),
-                     [this](const FieldDescriptor* f) {
-                       return !IsFieldUsed(f, options_);
-                     }),
-      ordered_fields.end());
 
   std::vector<const Descriptor::ExtensionRange*> sorted_extensions;
   sorted_extensions.reserve(descriptor_->extension_range_count());