Mojo: Add support for constants to the IDL compiler.

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 4e423aa8448506936c3602d687030926939f0769..f84ece2b403ebbd25d45a67f4d77a4a18b1dedbb 100644
--- a/mojo/public/tools/bindings/generators/cpp_templates/module.cc.tmpl
+++ b/mojo/public/tools/bindings/generators/cpp_templates/module.cc.tmpl
@@ -15,6 +15,12 @@
 {%- for namespace in namespaces_as_array %}
 namespace {{namespace}} {
 {%- endfor %}
+
+{#--- Constants #}
+{%  for constant in module.constants %}
+const {{constant.kind|cpp_pod_type}} {{constant.name}} = {{constant.value|expression_to_text(module)}};
+{%- endfor %}
+
 namespace internal {
 namespace {
 
@@ -50,6 +56,13 @@ const uint32_t {{method_name}} = {{method.ordinal}};
 
 }  // namespace internal
 
+{#--- Struct Constants #}
+{%- for struct in structs %}
+{%     for constant in struct.constants %}
+const {{constant.kind|cpp_pod_type}} {{struct.name}}::{{constant.name}} = {{constant.value|expression_to_text(module)}};
+{%-   endfor %}
+{%- endfor %}
+
 {#--- Struct builder definitions #}
 {%- for struct in structs %}
 {%-   include "struct_builder_definition.tmpl" %}