Change mojo enums to be scoped enums in the generated C++ bindings.

mojo/public/tools/bindings/generators/mojom_cpp_generator.py

Index: mojo/public/tools/bindings/generators/mojom_cpp_generator.py
diff --git a/mojo/public/tools/bindings/generators/mojom_cpp_generator.py b/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
index 0733e1a8e050e6b69691d879fdd14766db8e7482..0b1e867c9bcc9638cf79ef21a00d232395aee4f7 100644
--- a/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
+++ b/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
@@ -334,8 +334,7 @@ def TranslateConstants(token, kind):
     if token.parent_kind:
       name.append(token.parent_kind.name)
     if isinstance(token, mojom.EnumValue):
-      name.append(
-          "%s_%s" % (generator.CamelCaseToAllCaps(token.enum.name), token.name))
+      name.extend([token.enum.name, token.name])
     else:
       name.append(token.name)
     return "::".join(name)