[tracing] Add support for profiling trace events

base/trace_event/trace_log.h

Index: base/trace_event/trace_log.h
diff --git a/base/trace_event/trace_log.h b/base/trace_event/trace_log.h
index 67477c43f22f430dac1776f53af1f38d76e87a92..e715a52e9706dacb22366b477cd791da9f9fc6a9 100644
--- a/base/trace_event/trace_log.h
+++ b/base/trace_event/trace_log.h
@@ -60,7 +60,13 @@ class BASE_EXPORT TraceLog : public MemoryDumpProvider {
     // Category group enabled by SetEventCallbackEnabled().
     ENABLED_FOR_EVENT_CALLBACK = 1 << 2,
     // Category group enabled to export events to ETW.
-    ENABLED_FOR_ETW_EXPORT = 1 << 3
+    ENABLED_FOR_ETW_EXPORT = 1 << 3,
+    // Category group enabled for heap profiling.
+    ENABLED_FOR_HEAP_PROFILING = 1 << 4,

[fmeawad, 2016/04/01 15:54:46]

nit: maybe ENABLED_FOR_PROFILING, the name should convey that it is enabled for
pseudo-stack operations in general and not necessarily heap profiling.

+    // Enabled for any of the non-profiling modes.
+    ENABLED_FOR_NON_PROFILING_MODE = ENABLED_FOR_RECORDING |

[fmeawad, 2016/04/01 15:54:46]

nit: maybe ENABLED_FOR_TRACING

+                                     ENABLED_FOR_EVENT_CALLBACK |
+                                     ENABLED_FOR_ETW_EXPORT
   };
 
   static TraceLog* GetInstance();