[mojo] Add typemap and variant support to generators

mojo/public/tools/bindings/generators/cpp_templates/module.cc.tmpl

Index: mojo/public/tools/bindings/generators/cpp_templates/module.cc.tmpl
diff --git a/mojo/public/tools/bindings/generators/cpp_templates/module.cc.tmpl b/mojo/public/tools/bindings/generators/cpp_templates/module.cc.tmpl
index dddb6abbecf3d041e01171dfbbd996049fa5b6d5..fd2f610fee6f157076ef7cf651a8a47bca270cc6 100644
--- a/mojo/public/tools/bindings/generators/cpp_templates/module.cc.tmpl
+++ b/mojo/public/tools/bindings/generators/cpp_templates/module.cc.tmpl
@@ -2,6 +2,12 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+{%- if variant -%}
+{%-   set variant_path = "%s-%s"|format(module.path, variant) -%}
+{%- else -%}
+{%-   set variant_path = module.path -%}
+{%- endif %}
+
 #if defined(__clang__)
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wunused-private-field"
@@ -12,7 +18,7 @@
 #pragma warning(disable:4756)
 #endif
 
-#include "{{module.path}}.h"
+#include "{{variant_path}}.h"
 
 #include <math.h>
 
@@ -34,6 +40,9 @@
 {%- for namespace in namespaces_as_array %}
 namespace {{namespace}} {
 {%- endfor %}
+{%- if variant %}
+namespace {{variant}} {
+{%- endif %}
 
 {#--- Constants #}
 {%- for constant in module.constants %}
@@ -121,6 +130,9 @@ MOJO_STATIC_CONST_MEMBER_DEFINITION const {{constant.kind|cpp_pod_type}} {{struc
 {%-   include "union_serialization_definition.tmpl" %}
 {%- endfor %}
 
+{%- if variant %}
+}  // namespace {{variant}}
+{%- endif %}
 {%- for namespace in namespaces_as_array|reverse %}
 }  // namespace {{namespace}}
 {%- endfor %}