Implement a new flow event API that allows binding flow events and regular events.

content/child/blink_platform_impl.cc

Index: content/child/blink_platform_impl.cc
diff --git a/content/child/blink_platform_impl.cc b/content/child/blink_platform_impl.cc
index d743fffac4636fee02a2845e2dc1a113205cf13d..6cbb4994fd12cedb9669fdfee2f39b4dcecc146f 100644
--- a/content/child/blink_platform_impl.cc
+++ b/content/child/blink_platform_impl.cc
@@ -635,9 +635,19 @@ blink::Platform::TraceEventHandle BlinkPlatformImpl::addTraceEvent(
       base::TraceTicks() + base::TimeDelta::FromSecondsD(timestamp);
   base::trace_event::TraceEventHandle handle =
       TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP(
-          phase, category_group_enabled, name, id, trace_event_internal::kNoId,
-          base::PlatformThread::CurrentId(), timestamp_tt, num_args, arg_names,
-          arg_types, arg_values, NULL, flags);
+          phase,
+          category_group_enabled,
+          name,
+          id,
+          trace_event_internal::kNoId,  // context_id
+          base::PlatformThread::CurrentId(),

[beaudoin, 2015/07/29 18:55:43]

Should you have one for CurrentId()? It is it's unclead what it's for from the
variable name.

+          timestamp_tt,
+          num_args,
+          arg_names,
+          arg_types,
+          arg_values,
+          NULL,
+          flags);
   blink::Platform::TraceEventHandle result;
   memcpy(&result, &handle, sizeof(result));
   return result;
@@ -671,9 +681,19 @@ blink::Platform::TraceEventHandle BlinkPlatformImpl::addTraceEvent(
       base::TraceTicks() + base::TimeDelta::FromSecondsD(timestamp);
   base::trace_event::TraceEventHandle handle =
       TRACE_EVENT_API_ADD_TRACE_EVENT_WITH_THREAD_ID_AND_TIMESTAMP(
-          phase, category_group_enabled, name, id, trace_event_internal::kNoId,
-          base::PlatformThread::CurrentId(), timestamp_tt, num_args, arg_names,
-          arg_types, arg_values, convertable_wrappers, flags);
+          phase,
+          category_group_enabled,
+          name,
+          id,
+          trace_event_internal::kNoId,  // context_id
+          base::PlatformThread::CurrentId(),

[beaudoin, 2015/07/29 18:55:43]

Ditto.

+          timestamp_tt,
+          num_args,
+          arg_names,
+          arg_types,
+          arg_values,
+          convertable_wrappers,
+          flags);
   blink::Platform::TraceEventHandle result;
   memcpy(&result, &handle, sizeof(result));
   return result;