compiler: Remove unused function (#6911)

diff --git a/compiler/src/java_plugin/cpp/java_generator.cpp b/compiler/src/java_plugin/cpp/java_generator.cpp
index db914ce..695ef85 100644
--- a/compiler/src/java_plugin/cpp/java_generator.cpp
+++ b/compiler/src/java_plugin/cpp/java_generator.cpp
@@ -161,10 +161,6 @@
   return "METHODID_" + ToAllUpperCase(method->name());
 }
 
-static inline bool ShouldGenerateAsLite(const Descriptor* desc) {
-  return false;
-}
-
 static inline std::string MessageFullJavaName(const Descriptor* desc) {
   return google::protobuf::compiler::java::ClassName(desc);
 }