Support custom message filtering on Mojo binding objects

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

Index: mojo/public/tools/bindings/generators/cpp_templates/interface_definition.tmpl
diff --git a/mojo/public/tools/bindings/generators/cpp_templates/interface_definition.tmpl b/mojo/public/tools/bindings/generators/cpp_templates/interface_definition.tmpl
index 8a8c6f9bb65493bc5e3a1eb2c4f74a1cfd36609f..fa147259ff08b056c91612ca9ac0c0cc6b65c2b7 100644
--- a/mojo/public/tools/bindings/generators/cpp_templates/interface_definition.tmpl
+++ b/mojo/public/tools/bindings/generators/cpp_templates/interface_definition.tmpl
@@ -377,13 +377,7 @@ bool {{class_name}}Stub::AcceptWithResponder(
 
 {#--- Request validator definitions #}
 
-{{class_name}}RequestValidator::{{class_name}}RequestValidator(
-    mojo::MessageReceiver* sink) : MessageFilter(sink) {
-}
-
 bool {{class_name}}RequestValidator::Accept(mojo::Message* message) {
-  assert(sink_);
-
   mojo::internal::ValidationContext validation_context(
     message->data(), message->data_num_bytes(), message->handles()->size(),
     message, "{{class_name}} RequestValidator");
@@ -391,7 +385,7 @@ bool {{class_name}}RequestValidator::Accept(mojo::Message* message) {
   if (mojo::internal::ControlMessageHandler::IsControlMessage(message)) {
     if (!mojo::internal::ValidateControlRequest(message, &validation_context))
       return false;
-    return sink_->Accept(message);
+    return true;
   }
 
   switch (message->header()->name) {
@@ -413,7 +407,7 @@ bool {{class_name}}RequestValidator::Accept(mojo::Message* message) {
                   message, &validation_context)) {
         return false;
       }
-      return sink_->Accept(message);
+      return true;
     }
 {%- endfor %}
     default:
@@ -429,13 +423,7 @@ bool {{class_name}}RequestValidator::Accept(mojo::Message* message) {
 
 {#--- Response validator definitions #}
 {% if interface|has_callbacks %}
-{{class_name}}ResponseValidator::{{class_name}}ResponseValidator(
-    mojo::MessageReceiver* sink) : MessageFilter(sink) {
-}
-
 bool {{class_name}}ResponseValidator::Accept(mojo::Message* message) {
-  assert(sink_);
-
   mojo::internal::ValidationContext validation_context(
     message->data(), message->data_num_bytes(), message->handles()->size(),
     message, "{{class_name}} ResponseValidator");
@@ -443,7 +431,7 @@ bool {{class_name}}ResponseValidator::Accept(mojo::Message* message) {
   if (mojo::internal::ControlMessageHandler::IsControlMessage(message)) {
     if (!mojo::internal::ValidateControlResponse(message, &validation_context))
       return false;
-    return sink_->Accept(message);
+    return true;
   }
 
   if (!mojo::internal::ValidateMessageIsResponse(message, &validation_context))
@@ -456,7 +444,7 @@ bool {{class_name}}ResponseValidator::Accept(mojo::Message* message) {
                     message, &validation_context)) {
         return false;
       }
-      return sink_->Accept(message);
+      return true;
     }
 {%- endfor %}
     default: