Add a ConvertableToTraceFormat type to the trace framework.

base/debug/trace_event_internal.h

Index: base/debug/trace_event_internal.h
diff --git a/base/debug/trace_event_internal.h b/base/debug/trace_event_internal.h
index 46495f4460c4d60e04d0345359a2dd441f332eb7..afafbe13ce24990f8679a4b0731c5d1171a1b433 100644
--- a/base/debug/trace_event_internal.h
+++ b/base/debug/trace_event_internal.h
@@ -731,6 +731,7 @@
 #define TRACE_VALUE_TYPE_POINTER      (static_cast<unsigned char>(5))
 #define TRACE_VALUE_TYPE_STRING       (static_cast<unsigned char>(6))
 #define TRACE_VALUE_TYPE_COPY_STRING  (static_cast<unsigned char>(7))
+#define TRACE_VALUE_TYPE_CONVERTABLE  (static_cast<unsigned char>(8))
 
 // Enum reflecting the scope of an INSTANT event. Must fit within
 // TRACE_EVENT_FLAG_SCOPE_MASK.
@@ -838,9 +839,11 @@ class TraceStringWithCopy {
 #define INTERNAL_DECLARE_SET_TRACE_VALUE(actual_type, \
                                          union_member, \
                                          value_type_id) \
-    static inline void SetTraceValue(actual_type arg, \
-                                     unsigned char* type, \
-                                     unsigned long long* value) { \
+    static inline void SetTraceValue( \
+        actual_type arg, \
+        unsigned char* type, \
+        unsigned long long* value, \
+        scoped_ptr<base::debug::ConvertableToJSON>* convertable_value) { \
       TraceValueUnion type_value; \
       type_value.union_member = arg; \
       *type = value_type_id; \
@@ -849,9 +852,11 @@ class TraceStringWithCopy {
 // Simpler form for int types that can be safely casted.
 #define INTERNAL_DECLARE_SET_TRACE_VALUE_INT(actual_type, \
                                              value_type_id) \
-    static inline void SetTraceValue(actual_type arg, \
-                                     unsigned char* type, \
-                                     unsigned long long* value) { \
+    static inline void SetTraceValue( \
+        actual_type arg, \
+        unsigned char* type, \
+        unsigned long long* value, \
+        scoped_ptr<base::debug::ConvertableToJSON>* convertable_value) { \
       *type = value_type_id; \
       *value = static_cast<unsigned long long>(arg); \
     }
@@ -879,15 +884,26 @@ INTERNAL_DECLARE_SET_TRACE_VALUE(const TraceStringWithCopy&, as_string,
 #undef INTERNAL_DECLARE_SET_TRACE_VALUE_INT
 
 // std::string version of SetTraceValue so that trace arguments can be strings.
-static inline void SetTraceValue(const std::string& arg,
-                                 unsigned char* type,
-                                 unsigned long long* value) {
+static inline void SetTraceValue(
+    const std::string& arg,
+    unsigned char* type,
+    unsigned long long* value,
+    scoped_ptr<base::debug::ConvertableToJSON>* convertable_value) {
   TraceValueUnion type_value;
   type_value.as_string = arg.c_str();
   *type = TRACE_VALUE_TYPE_COPY_STRING;
   *value = type_value.as_uint;
 }
 
+static inline void SetTraceValue(
+    base::debug::ConvertableToJSON* arg,

[dsinclair, 2013/04/09 22:37:45]

This has to be scoped_ptr<base::debug::ConvertableToJSON> arg.

[dsinclair, 2013/04/10 01:09:31]

Done.

+    unsigned char* type,
+    unsigned long long* value,
+    scoped_ptr<base::debug::ConvertableToJSON>* convertable_value) {
+  *type = TRACE_VALUE_TYPE_CONVERTABLE;
+  convertable_value->reset(arg);
+}
+
 // These AddTraceEvent and AddTraceEventWithThreadIdAndTimestamp template
 // functions are defined here instead of in the macro, because the arg_values
 // could be temporary objects, such as std::string. In order to store
@@ -903,7 +919,7 @@ static inline void AddTraceEventWithThreadIdAndTimestamp(char phase,
     unsigned char flags) {
   TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP(
       phase, category_enabled, name, id, thread_id, timestamp,
-      kZeroNumArgs, NULL, NULL, NULL, flags);
+      kZeroNumArgs, NULL, NULL, NULL, NULL, flags);
 }
 
 static inline void AddTraceEvent(char phase,
@@ -930,10 +946,12 @@ static inline void AddTraceEventWithThreadIdAndTimestamp(char phase,
   const int num_args = 1;
   unsigned char arg_types[1];
   unsigned long long arg_values[1];
-  SetTraceValue(arg1_val, &arg_types[0], &arg_values[0]);
+  scoped_ptr<base::debug::ConvertableToJSON> convertable_values[1];
+  SetTraceValue(arg1_val, &arg_types[0], &arg_values[0],
+                &convertable_values[0]);
   TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP(
       phase, category_enabled, name, id, thread_id, timestamp,
-      num_args, &arg1_name, arg_types, arg_values, flags);
+      num_args, &arg1_name, arg_types, arg_values, convertable_values, flags);
 }
 
 template<class ARG1_TYPE>
@@ -967,11 +985,14 @@ static inline void AddTraceEventWithThreadIdAndTimestamp(char phase,
   const char* arg_names[2] = { arg1_name, arg2_name };
   unsigned char arg_types[2];
   unsigned long long arg_values[2];
-  SetTraceValue(arg1_val, &arg_types[0], &arg_values[0]);
-  SetTraceValue(arg2_val, &arg_types[1], &arg_values[1]);
+  scoped_ptr<base::debug::ConvertableToJSON> convertable_values[2];
+  SetTraceValue(arg1_val, &arg_types[0], &arg_values[0],
+                &convertable_values[0]);
+  SetTraceValue(arg2_val, &arg_types[1], &arg_values[1],
+                &convertable_values[1]);
   TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP(
       phase, category_enabled, name, id, thread_id, timestamp,
-      num_args, arg_names, arg_types, arg_values, flags);
+      num_args, arg_names, arg_types, arg_values, convertable_values, flags);
 }
 
 template<class ARG1_TYPE, class ARG2_TYPE>
@@ -1017,7 +1038,7 @@ class TRACE_EVENT_API_CLASS_EXPORT TraceEndOnScopeClose {
           TRACE_EVENT_PHASE_END,
           p_data_->category_enabled,
           p_data_->name, kNoEventId,
-          kZeroNumArgs, NULL, NULL, NULL,
+          kZeroNumArgs, NULL, NULL, NULL, NULL,
           TRACE_EVENT_FLAG_NONE);
     }
   }