Remove dependency on ui from view_manager.

mojo/public/tools/bindings/generators/cpp_templates/wrapper_class_declaration.tmpl

Index: mojo/public/tools/bindings/generators/cpp_templates/wrapper_class_declaration.tmpl
diff --git a/mojo/public/tools/bindings/generators/cpp_templates/wrapper_class_declaration.tmpl b/mojo/public/tools/bindings/generators/cpp_templates/wrapper_class_declaration.tmpl
index f6bea2c5dfb613db5149cc7a21480f13fd02c877..25b39b30d0e5622390e3010e77dd2168224d8a57 100644
--- a/mojo/public/tools/bindings/generators/cpp_templates/wrapper_class_declaration.tmpl
+++ b/mojo/public/tools/bindings/generators/cpp_templates/wrapper_class_declaration.tmpl
@@ -19,6 +19,11 @@ class {{struct.name}} {
     return mojo::TypeConverter<{{struct.name}}Ptr, U>::Convert(u);
   }
 
+  template <typename U>
+  U To() const {
+    return mojo::TypeConverter<U, {{struct.name}}>::Convert(*this);
+  }
+
   {{struct.name}}();
   ~{{struct.name}}();