headless: Ensure all commands have parameters and return types

headless/lib/browser/domain_h.template

 // This file is generated
 
 // Copyright (c) 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef HEADLESS_PUBLIC_DOMAINS_{{domain.domain | camelcase_to_hacker_style | upper}}_H_
 #define HEADLESS_PUBLIC_DOMAINS_{{domain.domain | camelcase_to_hacker_style | upper}}_H_
 
 #include "base/callback.h"
 #include "base/observer_list.h"
 #include "base/values.h"
 #include "headless/public/domains/types.h"
 #include "headless/public/headless_export.h"
 #include "headless/public/internal/message_dispatcher.h"
 
 {# Macro for defining a member function for a given command. #}
 {% macro command_decl(command) %}
   {% set method_name = command.name | to_title_case %}
   {% if command.description %}
   // {{ command.description }}
   {% endif %}
-  {% if "parameters" in command and "returns" in command %}
   void {{method_name}}(std::unique_ptr<{{method_name}}Params> params, base::Callback<void(std::unique_ptr<{{method_name}}Result>)> callback = base::Callback<void(std::unique_ptr<{{method_name}}Result>)>());
-  {% elif "parameters" in command %}
-  void {{method_name}}(std::unique_ptr<{{method_name}}Params> params, base::Callback<void()> callback = base::Callback<void()>());
-  {% elif "returns" in command %}
-  void {{method_name}}(base::Callback<void(std::unique_ptr<{{method_name}}Result>)> callback = base::Callback<void(std::unique_ptr<{{method_name}}Result>)>());
-  {% else %}
-  void {{method_name}}(base::Callback<void()> callback = base::Callback<void()>());
-  {% endif %}
   {# Generate convenience methods that take the required parameters directly. #}
   {# Don't generate these for experimental commands. #}
   {% if "parameters" in command and not command.experimental %}
   void {{method_name}}({##}
     {% for parameter in command.parameters -%}
       {% if parameter.get("optional", False) -%}
         {% break %}
       {% endif %}
       {% if not loop.first %}, {% endif %}
 {{resolve_type(parameter).pass_type}} {{parameter.name | camelcase_to_hacker_style -}}
     {% endfor %}
-    {% if "parameters" in command and not command.parameters[0].get("optional", False) %}, {% endif %}{# -#}
-    {% if "returns" in command -%}
+    {% if command.get("parameters", []) and not command.parameters[0].get("optional", False) %}, {% endif %}{# -#}
+    {% if command.get("returns", []) -%}
       base::Callback<void(std::unique_ptr<{{method_name}}Result>)> callback = base::Callback<void(std::unique_ptr<{{method_name}}Result>)>(){##}
     {% else -%}
       base::Callback<void()> callback = base::Callback<void()>(){##}
     {% endif %});
+    {# If the command has no return value, generate a convenience method that #}
+    {# accepts a base::Callback<void()> together with the parameters object. #}
+    {% if not command.get("returns", []) %}
+  void {{method_name}}(std::unique_ptr<{{method_name}}Params> params, base::Callback<void()> callback);
+    {% endif %}
   {% endif %}
 {% endmacro %}
 
 namespace headless {
 namespace {{domain.domain | camelcase_to_hacker_style}} {
 class ExperimentalDomain;
 class ExperimentalObserver;
 {% if "events" in domain %}
 
 class HEADLESS_EXPORT ExperimentalObserver {
@@ skipping 90 matching lines @@
   {% endfor %}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ExperimentalDomain);
 };
 
 }  // namespace {{domain.domain | camelcase_to_hacker_style}}
 }  // namespace headless
 
 #endif  // HEADLESS_PUBLIC_DOMAINS_{{domain.domain | camelcase_to_hacker_style | upper}}_H_