Add option to export tracing events to ETW.

base/trace_event/trace_event_impl.cc

Index: base/trace_event/trace_event_impl.cc
diff --git a/base/trace_event/trace_event_impl.cc b/base/trace_event/trace_event_impl.cc
index 72b46f92914c8d73d51068324f6c2a757371b5d1..d57481a67d5eec72359506dcd08786663178d616 100644
--- a/base/trace_event/trace_event_impl.cc
+++ b/base/trace_event/trace_event_impl.cc
@@ -35,6 +35,7 @@
 #include "base/trace_event/trace_event_synthetic_delay.h"
 
 #if defined(OS_WIN)
+#include "base/trace_event/trace_event_etw_export_win.h"
 #include "base/trace_event/trace_event_win.h"
 #endif
 
@@ -1290,6 +1291,11 @@ void TraceLog::UpdateCategoryGroupEnabledFlag(size_t category_index) {
   if (event_callback_ &&
       event_callback_category_filter_.IsCategoryGroupEnabled(category_group))
     enabled_flag |= ENABLED_FOR_EVENT_CALLBACK;
+#if defined(OS_WIN)
+  if (base::trace_event::TraceEventETWExport::isETWExportEnabled())
+    enabled_flag |= ENABLED_FOR_ETW_EXPORT;
+#endif
+
   g_category_group_enabled[category_index] = enabled_flag;
 }
 
@@ -1896,6 +1902,13 @@ TraceEventHandle TraceLog::AddTraceEventWithThreadIdAndTimestamp(
   if (!*category_group_enabled)
     return handle;
 
+#if defined(OS_WIN)
+  if (*category_group_enabled & ENABLED_FOR_ETW_EXPORT)

[dsinclair, 2015/03/26 18:18:17]

I think this should be down around where the android call is below.   We should
also move this to a method on TraceEvent like Android does with SendToATrace. So
this would have a SendToETW that would be called if needed.

[Georges Khalil, 2015/03/26 23:09:19]

After discussion, brought this down but before the lock gets acquired, as this
is not needed for ETW. It also saves us from creating the event if internal
tracing is not enabled.

+    TraceEventETWExport::AddEvent(phase, category_group_enabled, name, id,
+                                  num_args, arg_names, arg_types, arg_values,
+                                  convertable_values);
+#endif  // OS_WIN
+
   // Avoid re-entrance of AddTraceEvent. This may happen in GPU process when
   // ECHO_TO_CONSOLE is enabled: AddTraceEvent -> LOG(ERROR) ->
   // GpuProcessLogMessageHandler -> PostPendingTask -> TRACE_EVENT ...
@@ -2114,6 +2127,12 @@ void TraceLog::UpdateTraceEventDuration(
     const unsigned char* category_group_enabled,
     const char* name,
     TraceEventHandle handle) {
+#if defined(OS_WIN)
+  if (*category_group_enabled & ENABLED_FOR_ETW_EXPORT)
+    TraceEventETWExport::AddEvent(TRACE_EVENT_PHASE_END, category_group_enabled,

[dsinclair, 2015/03/26 18:18:17]

This isn't what you want here. This is just going to log an end phase, but you
lose the X event. The event is created down around line 2151 which is what needs
to be sent.

(Similar to how the event is SendToATrace())

[Georges Khalil, 2015/03/26 23:09:19]

After review and discussion, this code should be removed for now as there is no
notion of duration in ETW.

+                                  name, 0, 0, NULL, NULL, NULL, NULL);
+#endif  // OS_WIN
+
   // Avoid re-entrance of AddTraceEvent. This may happen in GPU process when
   // ECHO_TO_CONSOLE is enabled: AddTraceEvent -> LOG(ERROR) ->
   // GpuProcessLogMessageHandler -> PostPendingTask -> TRACE_EVENT ...