mojom: Add associative arrays to the mojom language.

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

Index: mojo/public/tools/bindings/generators/cpp_templates/interface_definition.tmpl
diff --git a/mojo/public/tools/bindings/generators/cpp_templates/interface_definition.tmpl b/mojo/public/tools/bindings/generators/cpp_templates/interface_definition.tmpl
index bb5b777346b0ac9fed58efb2bbf4c5ad5def354e..9cade2d118c5b6c9db554f18a709a3095fff7c8b 100644
--- a/mojo/public/tools/bindings/generators/cpp_templates/interface_definition.tmpl
+++ b/mojo/public/tools/bindings/generators/cpp_templates/interface_definition.tmpl
@@ -5,7 +5,14 @@
 
 {%- macro alloc_params(parameters) %}
 {%-   for param in parameters %}
-{%-     if param.kind|is_object_kind  %}
+{%-     if param.kind|is_map_kind  %}
+mojo::Array<{{param.kind.key_kind|cpp_result_type}}> p{{loop.index}}_keys;
+Deserialize_(params->{{param.name}}_keys.ptr, &p{{loop.index}}_keys);
+mojo::Array<{{param.kind.value_kind|cpp_result_type}}> p{{loop.index}}_values;
+Deserialize_(params->{{param.name}}_values.ptr, &p{{loop.index}}_values);
+{{param.kind|cpp_result_type}} p{{loop.index}}(p{{loop.index}}_keys.Pass(),
+                                               p{{loop.index}}_values.Pass());
+{%-     elif param.kind|is_object_kind  %}
 {{param.kind|cpp_result_type}} p{{loop.index}};
 Deserialize_(params->{{param.name}}.ptr, &p{{loop.index}});
 {%      endif -%}
@@ -33,12 +40,27 @@ params->{{param.name}}
 {%-   endfor %}
 {%- endmacro %}
 
+{%- macro mapping_prelude(parameters) -%}
+{%-   for param in parameters %}
+{%-     if param.kind|is_map_kind  %}
+  mojo::Array<{{param.kind.key_kind|cpp_result_type}}> in_{{param.name}}_keys;
+  mojo::Array<{{param.kind.value_kind|cpp_result_type}}> in_{{param.name}}_values;
+  in_{{param.name}}.DecomposeMapTo(&in_{{param.name}}_keys,
+                                   &in_{{param.name}}_values);
+{%-     endif -%}
+{%-   endfor -%}
+{%- endmacro %}
+
+
 {%- macro compute_payload_size(params_name, parameters) -%}
   size_t payload_size =
       mojo::internal::Align(sizeof({{params_name}}));
 {#--- Computes #}
 {%-   for param in parameters %}
-{%-     if param.kind|is_object_kind %}
+{%-     if param.kind|is_map_kind %}
+  payload_size += GetSerializedSize_(in_{{param.name}}_keys);
+  payload_size += GetSerializedSize_(in_{{param.name}}_values);
+{%-     elif param.kind|is_object_kind %}
   payload_size += GetSerializedSize_(in_{{param.name}});
 {%-     endif %}
 {%-   endfor %}
@@ -55,14 +77,30 @@ params->{{param.name}}
 {%-       if param.kind|is_any_array_kind %}
   mojo::SerializeArray_<{{param.kind|get_array_validate_params|indent(24)}}>(
       mojo::internal::Forward(in_{{param.name}}), builder.buffer(), &params->{{param.name}}.ptr);
+{%-     elif param.kind|is_map_kind %}
+  mojo::SerializeArray_<{{param.kind.key_kind|get_map_validate_params|indent(24)}}>(
+      mojo::internal::Forward(in_{{param.name}}_keys), builder.buffer(), &params->{{param.name}}_keys.ptr);
+  mojo::SerializeArray_<{{param.kind.value_kind|get_map_validate_params|indent(24)}}>(
+      mojo::internal::Forward(in_{{param.name}}_values), builder.buffer(), &params->{{param.name}}_values.ptr);
 {%-       else %}
   Serialize_(mojo::internal::Forward(in_{{param.name}}), builder.buffer(), &params->{{param.name}}.ptr);
 {%-       endif %}
 {%-       if not param.kind|is_nullable_kind %}
+{%-         if param.kind|is_map_kind %}
+  MOJO_INTERNAL_DLOG_SERIALIZATION_WARNING(
+      !params->{{param.name}}_keys.ptr,
+      mojo::internal::VALIDATION_ERROR_UNEXPECTED_NULL_POINTER,
+      "null key array for {{param.name}} argument in {{params_description}}");
+  MOJO_INTERNAL_DLOG_SERIALIZATION_WARNING(
+      !params->{{param.name}}_values.ptr,
+      mojo::internal::VALIDATION_ERROR_UNEXPECTED_NULL_POINTER,
+      "null key array for {{param.name}} argument in {{params_description}}");
+{%-         else %}
   MOJO_INTERNAL_DLOG_SERIALIZATION_WARNING(
       !params->{{param.name}}.ptr,
       mojo::internal::VALIDATION_ERROR_UNEXPECTED_NULL_POINTER,
       "null {{param.name}} argument in {{params_description}}");
+{%-         endif %}
 {%-       endif %}
 {%-     elif param.kind|is_any_handle_kind %}
 {%-       if param.kind|is_interface_kind or
@@ -138,6 +176,8 @@ bool {{class_name}}_{{method.name}}_ForwardToCallback::Accept(
           "%s.%s request"|format(interface.name, method.name) %}
 void {{proxy_name}}::{{method.name}}(
     {{interface_macros.declare_request_params("in_", method)}}) {
+  {{mapping_prelude(method.parameters)}}
+
   {{compute_payload_size(params_name, method.parameters)}}
 
 {%- if method.response_parameters != None %}
@@ -193,6 +233,8 @@ class {{class_name}}_{{method.name}}_ProxyToResponder
 };
 void {{class_name}}_{{method.name}}_ProxyToResponder::Run(
     {{interface_macros.declare_params("in_", method.response_parameters)}}) const {
+  {{mapping_prelude(method.response_parameters)}}
+
   {{compute_payload_size(params_name, method.response_parameters)}}
   mojo::internal::ResponseMessageBuilder builder(
       {{message_name}}, payload_size, request_id_);