Trace mojo async response parameters

Implement tracing of mojo async response parameters. Add a
|parameter_group| argument to |trace_event| macro to provide more
flexibility when naming the traced parameters.

Thus provide debugging information for asynchronous response parameters
as well.

Bug: 1103623
Change-Id: I7e38d8cc53ba8eff30c207defc0467674be50f3a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2339632
Commit-Queue: Karel Král <karelkral@google.com>
Reviewed-by: Alexander Timin <altimin@chromium.org>
Reviewed-by: Oksana Zhuravlova <oksamyt@chromium.org>
Cr-Commit-Position: refs/heads/master@{#797271}

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

@@ -121,8 +121,10 @@ bool {{proxy_name}}::{{method.name}}(
 #if BUILDFLAG(MOJO_TRACE_ENABLED)
 {%-     set qualified_method_name = "%s::%s::%s" % (namespace_as_string,
                                                     class_name, method.name) %}
-  {{interface_macros.trace_event("param_", method.parameters,
-                                 qualified_method_name,
+  {{interface_macros.trace_event(prefix="param_",
+                                 method_parameters=method.parameters,
+                                 method_name=qualified_method_name,
+                                 parameter_group="input_parameters",
                                  trace_event_type='_BEGIN')}}
 #endif
   const bool kExpectsResponse = true;
@@ -156,8 +158,10 @@ bool {{proxy_name}}::{{method.name}}(
 {%-     endfor %}));
   ignore_result(receiver_->AcceptWithResponder(&message, std::move(responder)));
 #if BUILDFLAG(MOJO_TRACE_ENABLED)
-  {{interface_macros.trace_event("out_param_", method.response_parameters,
-                                 qualified_method_name,
+  {{interface_macros.trace_event(prefix="out_param_",
+                                 method_parameters=method.response_parameters,
+                                 method_name=qualified_method_name,
+                                 parameter_group="sync_response_parameters",
                                  trace_event_type='_END',
                                  dereference_parameters=True)}}
 #endif
@@ -170,8 +174,10 @@ void {{proxy_name}}::{{method.name}}(
 #if BUILDFLAG(MOJO_TRACE_ENABLED)
 {%- set qualified_method_name = "%s::%s::%s" % (namespace_as_string, class_name,
                                                 method.name) %}
-  {{interface_macros.trace_event("in_", method.parameters,
-                                 qualified_method_name)}}
+  {{interface_macros.trace_event(prefix="in_",
+                                 method_parameters=method.parameters,
+                                 method_name=qualified_method_name,
+                                 parameter_group="input_parameters")}}
 #endif
 {%- if method.response_parameters != None %}
   const bool kExpectsResponse = true;
@@ -327,6 +333,16 @@ bool {{class_name}}_{{method.name}}_ForwardToCallback::Accept(
 
 void {{class_name}}_{{method.name}}_ProxyToResponder::Run(
     {{interface_macros.declare_params("in_", method.response_parameters)}}) {
+#if BUILDFLAG(MOJO_TRACE_ENABLED)
+{%-     set qualified_method_name = "(Impl)%s::%s::%sCallback"
+		% (namespace_as_string, class_name, method.name) %}
+  {{interface_macros.trace_event(prefix="in_",
+                                 method_parameters=method.response_parameters,
+                                 method_name=qualified_method_name,
+                                 parameter_group="async_response_parameters",
+                                 trace_event_type='_BEGIN',
+                                 dereference_parameters=False)}}
+#endif
 {%-   if method|method_supports_lazy_serialization %}
   const bool kSerialize = responder_->PrefersSerializedMessages();
   auto message = {{response_message_typename}}::Build(kSerialize, is_sync_
@@ -341,8 +357,8 @@ void {{class_name}}_{{method.name}}_ProxyToResponder::Run(
 {%-   endif %}
 
 #if BUILDFLAG(MOJO_TRACE_ENABLED)
-  TRACE_EVENT1("mojom", "(Impl){{namespace_as_string}}::{{class_name}}::{{method.name}}Callback",
-               "message", message.name());
+  TRACE_EVENT_END1("mojom", "{{qualified_method_name}}", "message",
+                   message.name());
 #endif
 
 #if defined(ENABLE_IPC_FUZZER)

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

@@ -24,7 +24,7 @@ base::OnceCallback<void(
 {%-   endif -%}
 {%- endmacro -%}
 
-{%- macro trace_event(prefix, method_parameters, qualified_method_name,
+{%- macro trace_event(prefix, method_parameters, method_name, parameter_group,
                       trace_event_type='', dereference_parameters=False) -%}
 {#- This macro assumes that the argument names are the ones declared by -#}
 {#- |declare_request_params/declare_sync_method_params|. Namely the |prefix| -#}
@@ -40,12 +40,7 @@ base::OnceCallback<void(
 {#- |dereference_parameters| the parameters type is actually |kind*|. -#}
 {%-   if method_parameters -%}
   TRACE_EVENT{{trace_event_type}}1(
-{%-     if trace_event_type=='' or trace_event_type=='_BEGIN' -%}
-{%-       set parameter_group = 'input_parameters' -%}
-{%-     else -%}
-{%-       set parameter_group = 'response_parameters' -%}
-{%-     endif  %}
-    "mojom", "{{qualified_method_name}}", "{{parameter_group}}",
+    "mojom", "{{method_name}}", "{{parameter_group}}",
     [&](){
       auto value = std::make_unique<base::trace_event::TracedValue>();
       base::trace_event::TracedValue* raw_value = value.get();
@@ -75,7 +70,7 @@ base::OnceCallback<void(
       return value;
     }());
 {%-   else -%}  {#- if method_parameters -#}
-  TRACE_EVENT{{trace_event_type}}0("mojom", "{{qualified_method_name}}");
+  TRACE_EVENT{{trace_event_type}}0("mojom", "{{method_name}}");
 {%-   endif %}  {#- if method_parameters #}
 {%- endmacro -%}