[New go generator] Implement declaring unions.

mojom/generators/go/templates/templates.go

Index: mojom/generators/go/templates/templates.go
diff --git a/mojom/generators/go/templates/templates.go b/mojom/generators/go/templates/templates.go
index fd725af0d305aec6ebf1b66bb08b48c4756a5b1a..866c9dcb2293f47120c7eb9083a0bc3af5bb9bea 100644
--- a/mojom/generators/go/templates/templates.go
+++ b/mojom/generators/go/templates/templates.go
@@ -34,6 +34,7 @@ func ExecuteTemplates(tmplFile *translator.TmplFile) string {
 func init() {
 	// We parse the subtemplates only once.
 	goFileTmpl = template.New("GoFileTemplate")
+
 	template.Must(goFileTmpl.Parse(goFileTemplate))
 	template.Must(goFileTmpl.Parse(nonNullableFieldDecodingTmplText))
 	template.Must(goFileTmpl.Parse(fieldDecodingTmplText))
@@ -44,6 +45,11 @@ func init() {
 	template.Must(goFileTmpl.Parse(structDeclTmplText))
 	template.Must(goFileTmpl.Parse(structVersions))
 	template.Must(goFileTmpl.Parse(structDecodingTmplText))
+
+	template.Must(goFileTmpl.Parse(unionDeclTmplText))
+	template.Must(goFileTmpl.Parse(unionInterfaceDeclTmplText))
+	template.Must(goFileTmpl.Parse(unionFieldDeclTmplText))
+	template.Must(goFileTmpl.Parse(unknownUnionFieldDeclTmplText))
 }
 
 const goFileTemplate = `
@@ -66,5 +72,9 @@ import (
 
 	{{ template "StructDecodingTmpl" $struct }}
 {{- end}}
+
+{{- range $union := $fileTmpl.Imports}}

[vardhan, 2016/06/08 20:45:47]

hm.. did you mean $fileTmpl.Unions?

and below this line, did you mean $union instead of $struct?

[azani, 2016/06/08 23:51:48]

Done.

+	{{ template "UnionDecl" $struct }}
+{{- end}}
 {{- end -}}
 `