Add support for constants in the new go generator.

mojom/generators/go/translator/mojom_file.go

Index: mojom/generators/go/translator/mojom_file.go
diff --git a/mojom/generators/go/translator/mojom_file.go b/mojom/generators/go/translator/mojom_file.go
index c4ed489b03119ed6723f588c0076ee9779771426..c90455c6d5fba3dc88affd846b2db4536747e07d 100644
--- a/mojom/generators/go/translator/mojom_file.go
+++ b/mojom/generators/go/translator/mojom_file.go
@@ -18,6 +18,7 @@ type TmplFile struct {
 	Unions                    []*UnionTemplate
 	Enums                     []*EnumTemplate
 	Interfaces                []*InterfaceTemplate
+  Constants                 []*ConstantTemplate

[vardhan, 2016/08/15 22:51:59]

tabs

[azani, 2016/08/15 23:49:39]

Done.

 	MojomImports              []string
 	SerializedRuntimeTypeInfo string
 }
@@ -222,6 +223,16 @@ type MethodTemplate struct {
 
 ////////////////////////////////////////////////////////////////////////////////
 
+type ConstantTemplate struct {
+  Name string
+

[vardhan, 2016/08/15 22:51:59]

empty spaces not necessary if there are no comments?

[azani, 2016/08/15 23:49:39]

Done.

+  Type string
+
+  Value string
+}
+
+////////////////////////////////////////////////////////////////////////////////
+
 // EncodingInfo describes the information necessary to encode a field.
 type EncodingInfo interface {
 	// IsSimple returns true if the field is a numeric type, boolean or string.