Move StringSpaceUsedIncludingSelf to lite library.

This came up because Chromium downstream modifies the lite library in a way that
requires this function, but I'm upstreaming it because based on the comments in
repeated_field.h, this ought to allow resolution of an existing hack.

I don't know enough about the protobuf code to feel confident trying to resolve
this hack myself, so I've merely updated the TODO comments.

src/google/protobuf/generated_message_reflection.cc

@@ -57,18 +57,6 @@ bool IsMapFieldInApi(const FieldDescriptor* field) {
 }
 }  // anonymous namespace
 
-int StringSpaceUsedExcludingSelf(const string& str) {
-  const void* start = &str;
-  const void* end = &str + 1;
-
-  if (start <= str.data() && str.data() < end) {
-    // The string's data is stored inside the string object itself.
-    return 0;
-  } else {
-    return str.capacity();
-  }
-}
-
 bool ParseNamedEnum(const EnumDescriptor* descriptor,
                     const string& name,
                     int* value) {

src/google/protobuf/generated_message_util.cc

@@ -60,6 +60,18 @@ void InitEmptyString() {
   OnShutdown(&DeleteEmptyString);
 }
 
+int StringSpaceUsedExcludingSelf(const string& str) {
+  const void* start = &str;
+  const void* end = &str + 1;
+
+  if (start <= str.data() && str.data() < end) {
+    // The string's data is stored inside the string object itself.
+    return 0;
+  } else {
+    return str.capacity();
+  }
+}
+
 
 }  // namespace internal
 }  // namespace protobuf

src/google/protobuf/generated_message_util.h

@@ -89,12 +89,6 @@ LIBPROTOBUF_EXPORT inline const ::std::string& GetEmptyString() {
   return GetEmptyStringAlreadyInited();
 }
 
-// Defined in generated_message_reflection.cc -- not actually part of the lite
-// library.
-//
-// TODO(jasonh): The various callers get this declaration from a variety of
-// places: probably in most cases repeated_field.h. Clean these up so they all
-// get the declaration from this file.
 LIBPROTOBUF_EXPORT int StringSpaceUsedExcludingSelf(const string& str);
 
 

src/google/protobuf/repeated_field.h

@@ -647,7 +647,8 @@ inline const Message& GenericTypeHandler<Message>::default_instance() {
 //   StringTypeHandler is exported.  So, we factor out StringTypeHandlerBase,
 //   export that, then make StringTypeHandler be a subclass which is NOT
 //   exported.
-// TODO(kenton):  There has to be a better way.
+// TODO(kenton):  Now that StringSpaceUsedExcludingSelf() is in the lite
+//   library, this can be cleaned up.
 class LIBPROTOBUF_EXPORT StringTypeHandlerBase {
  public:
   typedef string Type;