Mojo: Move mojo/public/bindings to mojo/public/tools/bindings.

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

 {%- set class_name = struct.name -%}
 {%- set dtor_name = [] %}
 {%- if struct|is_struct_with_handles %}
 {%-   set _ = dtor_name.append("&internal::%s_Data_Destructor"|format(struct.name)) %}
 {%- else %}
 {%-   set _ = dtor_name.append("NULL") %}
 {%- endif %}
 
 {%- macro set_default(kind, value, depth) -%}
 {#--- Strings ---#}
@@ skipping 45 matching lines @@
 {%-     endcall %}
 {%-   endfilter %}
 {%- endfor %}
 }
 
 {{class_name}} {{class_name}}::Builder::Finish() {
   Data* data = NULL;
   std::swap(data, data_);
   return mojo::internal::Wrap(data);
 }