More 'int' return value documentation

src/google/protobuf/compiler/java/java_message.h

@@ -67,7 +67,7 @@ class MessageGenerator {
   virtual void GenerateStaticVariables(io::Printer* printer) = 0;
 
   // Output code which initializes the static variables generated by
-  // GenerateStaticVariables().
+  // GenerateStaticVariables(). Returns an estimate of bytecode size.
   virtual int GenerateStaticVariableInitializers(io::Printer* printer) = 0;
 
   // Generate the class itself.
@@ -97,6 +97,8 @@ class ImmutableMessageGenerator : public MessageGenerator {
   virtual void GenerateInterface(io::Printer* printer);
   virtual void GenerateExtensionRegistrationCode(io::Printer* printer);
   virtual void GenerateStaticVariables(io::Printer* printer);
+
+  // Returns an estimate of the number of bytes the printed code will compile to
   virtual int GenerateStaticVariableInitializers(io::Printer* printer);
 
  private:
@@ -106,6 +108,8 @@ class ImmutableMessageGenerator : public MessageGenerator {
   };
 
   void GenerateFieldAccessorTable(io::Printer* printer);
+
+  // Returns an estimate of the number of bytes the printed code will compile to
   int GenerateFieldAccessorTableInitializer(io::Printer* printer);
 
   void GenerateMessageSerializationMethods(io::Printer* printer);