Oilpan: GC profiling.

Source/platform/TraceEvent.h

Index: Source/platform/TraceEvent.h
diff --git a/Source/platform/TraceEvent.h b/Source/platform/TraceEvent.h
index b7f902a5e08a34b2b9bae2ddffcbe21ff0a92f26..16215573f97a4d4f255dbeaef8bfd6944c9a3da3 100644
--- a/Source/platform/TraceEvent.h
+++ b/Source/platform/TraceEvent.h
@@ -497,6 +497,11 @@
     INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_CREATE_OBJECT, \
         categoryGroup, name, TRACE_ID_DONT_MANGLE(id), TRACE_EVENT_FLAG_NONE)
 
+#define TRACE_EVENT_OBJECT_SNAPSHOT_WITH_ID(categoryGroup, name, id, snapshot) \
+    INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_SNAPSHOT_OBJECT, \
+        categoryGroup, name, TRACE_ID_DONT_MANGLE(id), TRACE_EVENT_FLAG_NONE, \
+        "snapshot", snapshot)
+
 #define TRACE_EVENT_OBJECT_DELETED_WITH_ID(categoryGroup, name, id) \
     INTERNAL_TRACE_EVENT_ADD_WITH_ID(TRACE_EVENT_PHASE_DELETE_OBJECT, \
         categoryGroup, name, TRACE_ID_DONT_MANGLE(id), TRACE_EVENT_FLAG_NONE)
@@ -643,6 +648,7 @@
 #define TRACE_EVENT_PHASE_COUNTER  ('C')
 #define TRACE_EVENT_PHASE_SAMPLE  ('P')
 #define TRACE_EVENT_PHASE_CREATE_OBJECT ('N')
+#define TRACE_EVENT_PHASE_SNAPSHOT_OBJECT ('O')
 #define TRACE_EVENT_PHASE_DELETE_OBJECT ('D')
 
 // Flags for changing the behavior of TRACE_EVENT_API_ADD_TRACE_EVENT.