[mojo] Add GenericInterface_ to interface class variants

mojo/public/tools/bindings/generators/mojom_cpp_generator.py

Index: mojo/public/tools/bindings/generators/mojom_cpp_generator.py
diff --git a/mojo/public/tools/bindings/generators/mojom_cpp_generator.py b/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
index 4c632702d67844693eb266087b14a024106ed23f..15e429f4f18abc095d32686345969449ac1c89f3 100644
--- a/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
+++ b/mojo/public/tools/bindings/generators/mojom_cpp_generator.py
@@ -67,6 +67,12 @@ def GetNameForKind(kind, internal = False):
   parts.append(kind.name)
   return "::".join(parts)
 
+def GetQualifiedGenericInterfaceName(interface_kind):
+  parts = [""]

[yzshen1, 2015/12/14 23:58:26]

Please comment on why having "" there. 

+  parts.extend(NamespaceToArray(interface_kind.module.namespace))
+  parts.append(interface_kind.name)
+  return "::".join(parts)
+
 def GetCppType(kind):
   if mojom.IsArrayKind(kind):
     return "mojo::internal::Array_Data<%s>*" % GetCppType(kind.kind)
@@ -390,6 +396,7 @@ class Generator(generator.Generator):
     "get_map_validate_params_ctor_args": GetMapValidateParamsCtorArgs,
     "get_name_for_kind": GetNameForKind,
     "get_pad": pack.GetPad,
+    "get_qualified_generic_interface_name": GetQualifiedGenericInterfaceName,
     "has_callbacks": mojom.HasCallbacks,
     "should_inline": ShouldInlineStruct,
     "should_inline_union": ShouldInlineUnion,