[mojo] Add typemap and variant support to generators

mojo/public/tools/bindings/generators/cpp_templates/module-internal.h.tmpl

Index: mojo/public/tools/bindings/generators/cpp_templates/module-internal.h.tmpl
diff --git a/mojo/public/tools/bindings/generators/cpp_templates/module-internal.h.tmpl b/mojo/public/tools/bindings/generators/cpp_templates/module-internal.h.tmpl
index 2d748fc95455cd23fb777ba83fcaa19d443f89e7..a3be5a4e2208696846edaa6dd304c4aa80ccbdce 100644
--- a/mojo/public/tools/bindings/generators/cpp_templates/module-internal.h.tmpl
+++ b/mojo/public/tools/bindings/generators/cpp_templates/module-internal.h.tmpl
@@ -2,8 +2,15 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-{%- set header_guard = "%s_INTERNAL_H_"|
-        format(module.path|upper|replace("/","_")|replace(".","_")) %}
+{%- if variant -%}
+{%-   set variant_path = "%s-%s"|format(module.path, variant) -%}
+{%- else -%}
+{%-   set variant_path = module.path -%}
+{%- endif -%}
+
+{%- set header_guard = "%s_INTERNAL_H_"|format(
+        variant_path|upper|replace("/","_")|replace(".","_")|
+            replace("-", "_")) %}
 
 #ifndef {{header_guard}}
 #define {{header_guard}}
@@ -27,6 +34,9 @@ class BoundsChecker;
 {%- for namespace in namespaces_as_array %}
 namespace {{namespace}} {
 {%- endfor %}
+{%- if variant %}
+namespace {{variant}} {
+{%- endif %}
 
 {#--- Wrapper forward declarations #}
 {%  for struct in structs %}
@@ -65,6 +75,9 @@ class {{union.name}}_Data;
 #pragma pack(pop)
 
 }  // namespace internal
+{%- if variant %}
+}  // namespace {{variant}}
+{%- endif %}
 {%- for namespace in namespaces_as_array|reverse %}
 }  // namespace {{namespace}}
 {%- endfor %}