[tracing] Support ConvertableToTraceFormat argument type.

src/tracing/trace-event.h

Index: src/tracing/trace-event.h
diff --git a/src/tracing/trace-event.h b/src/tracing/trace-event.h
index 06f8990ec80e4f4463e3034d4b2987b2e821e480..85da5eddd730c130509910c5e1b22432e679f198 100644
--- a/src/tracing/trace-event.h
+++ b/src/tracing/trace-event.h
@@ -6,6 +6,7 @@
 #define SRC_TRACING_TRACE_EVENT_H_
 
 #include <stddef.h>
+#include <memory>
 
 #include "base/trace_event/common/trace_event_common.h"
 #include "include/v8-platform.h"
@@ -494,6 +495,18 @@ INTERNAL_DECLARE_SET_TRACE_VALUE(const TraceStringWithCopy&, as_string,
 #undef INTERNAL_DECLARE_SET_TRACE_VALUE
 #undef INTERNAL_DECLARE_SET_TRACE_VALUE_INT
 
+static V8_INLINE void SetTraceValue(ConvertableToTraceFormat* convertable_value,
+                                    unsigned char* type, uint64_t* value) {
+  *type = TRACE_VALUE_TYPE_CONVERTABLE;
+  *value = static_cast<uint64_t>(reinterpret_cast<intptr_t>(convertable_value));
+}
+
+template <typename T>
+static V8_INLINE void SetTraceValue(std::unique_ptr<T>&& ptr,

[caseq, 2016/09/23 01:00:50]

This does not look well -- we thus accept unique_ptrs to anything, but will only
properly manage ownership for those that are parametrized as
ConvertableToTraceFormat. Should this one just be non-template?

Also, style guide forbids rvalue refs usage outside of moveable constructors and
perfect forwarding.

[alph, 2016/09/23 06:33:24]

Done.

+                                    unsigned char* type, uint64_t* value) {
+  SetTraceValue(ptr.release(), type, value);
+}
+
 // These AddTraceEvent template
 // function is defined here instead of in the macro, because the arg_values
 // could be temporary objects, such as std::string. In order to store
@@ -514,28 +527,30 @@ template <class ARG1_TYPE>
 static V8_INLINE uint64_t AddTraceEvent(
     char phase, const uint8_t* category_group_enabled, const char* name,
     const char* scope, uint64_t id, uint64_t bind_id, unsigned int flags,
-    const char* arg1_name, const ARG1_TYPE& arg1_val) {
+    const char* arg1_name, ARG1_TYPE&& arg1_val) {
   const int num_args = 1;
-  uint8_t arg_types[1];
-  uint64_t arg_values[1];
-  SetTraceValue(arg1_val, &arg_types[0], &arg_values[0]);
+  uint8_t arg_type;
+  uint64_t arg_value;
+  SetTraceValue(std::forward<ARG1_TYPE>(arg1_val), &arg_type, &arg_value);
   return TRACE_EVENT_API_ADD_TRACE_EVENT(
       phase, category_group_enabled, name, scope, id, bind_id, num_args,
-      &arg1_name, arg_types, arg_values, flags);
+      &arg1_name, &arg_type, &arg_value, flags);
 }
 
 template <class ARG1_TYPE, class ARG2_TYPE>
 static V8_INLINE uint64_t AddTraceEvent(
     char phase, const uint8_t* category_group_enabled, const char* name,
     const char* scope, uint64_t id, uint64_t bind_id, unsigned int flags,
-    const char* arg1_name, const ARG1_TYPE& arg1_val, const char* arg2_name,
-    const ARG2_TYPE& arg2_val) {
+    const char* arg1_name, ARG1_TYPE&& arg1_val, const char* arg2_name,
+    ARG2_TYPE&& arg2_val) {
   const int num_args = 2;
   const char* arg_names[2] = {arg1_name, arg2_name};
   unsigned char arg_types[2];
   uint64_t arg_values[2];
-  SetTraceValue(arg1_val, &arg_types[0], &arg_values[0]);
-  SetTraceValue(arg2_val, &arg_types[1], &arg_values[1]);
+  SetTraceValue(std::forward<ARG1_TYPE>(arg1_val), &arg_types[0],
+                &arg_values[0]);
+  SetTraceValue(std::forward<ARG2_TYPE>(arg2_val), &arg_types[1],
+                &arg_values[1]);
   return TRACE_EVENT_API_ADD_TRACE_EVENT(
       phase, category_group_enabled, name, scope, id, bind_id, num_args,
       arg_names, arg_types, arg_values, flags);