Port messages sent by WebIDBFactoryImpl to Mojo.

mojo/public/tools/bindings/mojom.gni

Index: mojo/public/tools/bindings/mojom.gni
diff --git a/mojo/public/tools/bindings/mojom.gni b/mojo/public/tools/bindings/mojom.gni
index be36cb49d6200e1ea6742b1bceeb4a5bcbd6aba6..ef15a5e0c7a1ddea5bc6bf538c601a1d6f5c6a7b 100644
--- a/mojo/public/tools/bindings/mojom.gni
+++ b/mojo/public/tools/bindings/mojom.gni
@@ -209,6 +209,9 @@ template("mojom") {
   # Generate code for variants.
   foreach(bindings_configuration, _bindings_configurations) {
     cpp_only = false
+    if (defined(invoker.cpp_only)) {

[Ken Rockot(use gerrit already), 2016/09/28 20:06:44]

Oh, I thought we had already exposed this. Can you please briefly document this
at the top of the GNI along with the other variables?

[Reilly Grant (use Gerrit), 2016/09/29 06:44:50]

Done.

+      cpp_only = invoker.cpp_only
+    }
     variant_suffix = ""
     if (defined(bindings_configuration.variant)) {
       variant = bindings_configuration.variant