Enable the method AsValueInto on mojo

Stop hiding the mojo auto-generated method AsValueInto behind the build flag MOJO_TRACE_ENABLED to allow emitting traces from non-generated code. Thus there would be no need to write custom trace methods by hand and to keep them up-to-date.

Bug: 1103623
Change-Id: Ibdc45d15e21c9edc9324fe1f9614f4435d00e2d7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2351999Reviewed-by: Oksana Zhuravlova <oksamyt@chromium.org>
Reviewed-by: Alexander Timin <altimin@chromium.org>
Commit-Queue: Karel Král <karelkral@google.com>
Cr-Commit-Position: refs/heads/master@{#798057}

mojo/public/tools/bindings/generators/cpp_templates/module.cc.tmpl

@@ -25,7 +25,10 @@
 
 #include "base/hash/md5_constexpr.h"
 #include "base/run_loop.h"
+#include "base/strings/string_number_conversions.h"
 #include "base/task/common/task_annotator.h"
+#include "base/trace_event/trace_conversion_helper.h"
+#include "base/trace_event/traced_value.h"
 #include "mojo/public/cpp/bindings/lib/generated_code_util.h"
 #include "mojo/public/cpp/bindings/lib/message_internal.h"
 #include "mojo/public/cpp/bindings/lib/serialization_util.h"

mojo/public/tools/bindings/generators/cpp_templates/module.h.tmpl

@@ -51,11 +51,8 @@ namespace {{variant}} {
 
 #include "mojo/public/cpp/bindings/mojo_buildflags.h"
 #if BUILDFLAG(MOJO_TRACE_ENABLED)
-#include "base/strings/string_number_conversions.h"
-#include "base/trace_event/trace_conversion_helper.h"
 #include "base/trace_event/trace_event.h"
-#include "base/trace_event/traced_value.h"
-#endif
+#endif  // BUILDFLAG(MOJO_TRACE_ENABLED)
 #include "mojo/public/cpp/bindings/clone_traits.h"
 #include "mojo/public/cpp/bindings/equals_traits.h"
 #include "mojo/public/cpp/bindings/lib/serialization.h"
@@ -144,6 +141,14 @@ namespace {{variant}} {
 {%-   endfor %}
 {%- endif %}
 
+// Forward-declare for |AsValueInto| so that we do not have to import the
+// corresponding header.
+namespace base {
+namespace trace_event {
+class TracedValue;
+}  // namespace trace_event
+}  // namespace base
+
 {{namespace_begin()}}
 
 {%- set module_prefix = "%s"|format(namespaces_as_array|join(".")) %}

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

@@ -128,7 +128,6 @@ class {{export_attribute}} {{struct.name}} {
   {{type}} {{name}};
 {%- endfor %}
 
-#if BUILDFLAG(MOJO_TRACE_ENABLED)
   // Write this structure into |value|. The members are represented as a
   // dictionary |member name|: |member value|. This method does not deal with
   // the dictionary name. The caller is responsible for not calling
@@ -177,7 +176,6 @@ class {{export_attribute}} {{struct.name}} {
   //   b.AsValueInto(value1);
   //   c.AsValueInto(value2);
   void AsValueInto(base::trace_event::TracedValue* value) const;
-#endif  // BUILDFLAG(MOJO_TRACE_ENABLED)
 
  private:
   static bool Validate(const void* data,

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

@@ -32,7 +32,6 @@ size_t {{struct.name}}::Hash(size_t seed) const {
 }
 {%- endif %}
 
-#if BUILDFLAG(MOJO_TRACE_ENABLED)
 void {{struct.name}}::AsValueInto(base::trace_event::TracedValue* value) const {
 {%-  for field in struct.fields %}
 {%-    for line in field.kind|write_input_param_for_tracing(
@@ -43,7 +42,6 @@ void {{struct.name}}::AsValueInto(base::trace_event::TracedValue* value) const {
 {%-    endfor -%}
 {%-  endfor %}
 }
-#endif  // BUILDFLAG(MOJO_TRACE_ENABLED)
 
 bool {{struct.name}}::Validate(
     const void* data,