[Draft] try out the idea of adding export macros for C++ bindings.

mojo/public/tools/bindings/mojom_bindings_generator.py

Index: mojo/public/tools/bindings/mojom_bindings_generator.py
diff --git a/mojo/public/tools/bindings/mojom_bindings_generator.py b/mojo/public/tools/bindings/mojom_bindings_generator.py
index 18b9496daf6620d87aa3a8188b93408df3aba37b..675251c5c6843402f01f4783927e0a1f1797aaa9 100755
--- a/mojo/public/tools/bindings/mojom_bindings_generator.py
+++ b/mojo/public/tools/bindings/mojom_bindings_generator.py
@@ -143,7 +143,9 @@ class MojomProcessor(object):
       for language, generator_module in generator_modules.iteritems():
         generator = generator_module.Generator(
             module, args.output_dir, typemap=self._typemap.get(language, {}),
-            variant=args.variant, bytecode_path=args.bytecode_path)
+            variant=args.variant, bytecode_path=args.bytecode_path,
+            dll_export_declaration=args.dll_export_declaration,
+            dll_export_include=args.dll_export_include)
         filtered_args = []
         if hasattr(generator_module, 'GENERATOR_PREFIX'):
           prefix = '--' + generator_module.GENERATOR_PREFIX + '_'
@@ -252,6 +254,12 @@ def main():
           "the path from which to load template bytecode; to generate template "
           "bytecode, run %s precompile BYTECODE_PATH" % os.path.basename(
               sys.argv[0])))
+  generate_parser.add_argument(
+      "--dll_export_declaration", type=str,
+      help="TODO(yzshen)")
+  generate_parser.add_argument(
+      "--dll_export_include", type=str,
+      help="TODO(yzshen)")
   generate_parser.set_defaults(func=_Generate)
 
   precompile_parser = subparsers.add_parser("precompile",