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

cc/output/latency_info_swap_promise.cc

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/output/latency_info_swap_promise.h"
 
 #include "base/logging.h"
 #include "base/trace_event/trace_event.h"
 
 namespace {
@@ skipping 34 matching lines @@
   // is enabled in GPU side.
   // DCHECK(latency_.terminated);
 }
 
 int64 LatencyInfoSwapPromise::TraceId() const {
   return latency_.trace_id;
 }
 
 // Trace the original LatencyInfo of a LatencyInfoSwapPromise
 void LatencyInfoSwapPromise::OnCommit() {
+  TRACE_EVENT_WITH_FLOW0("toplevel", "LatencyInfoSwapPromise::OnCommit",
+                         TRACE_ID_DONT_MANGLE(TraceId()),
+                         TRACE_EVENT_FLAG_FLOW_IN | TRACE_EVENT_FLAG_FLOW_OUT);
   TRACE_EVENT_FLOW_STEP0("input,benchmark", "LatencyInfo.Flow",
                          TRACE_ID_DONT_MANGLE(TraceId()),
                          "HanldeInputEventMainCommit");
 }
 
 }  // namespace cc