Mojo: Add support for constants to the IDL compiler.

mojo/public/tools/bindings/generators/cpp_templates/wrapper_class_declaration.tmpl

 class {{struct.name}} {
  public:
   typedef internal::{{struct.name}}_Data Data;
 
+{#--- Constants #}
+{%  for constant in struct.constants %}
+  static const {{constant.kind|cpp_pod_type}} {{constant.name}};
+{%- endfor %}
+
 {#--- Enums #}
 {%- for enum in struct.enums -%}
 {%    macro enum_def() %}{% include "enum_declaration.tmpl" %}{% endmacro %}
   {{enum_def()|indent(2)}}
 {%- endfor %}
 
   {{struct.name}}() : data_(NULL) {
   }
 
   template <typename U>
@@ skipping 71 matching lines @@
   };
 
  private:
   friend class mojo::internal::WrapperHelper<{{struct.name}}>;
 
   struct Wrap {};
   {{struct.name}}(Wrap, const Data* data) : data_(data) {}
 
   const Data* data_;
 };