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

ui/events/latency_info.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 "ui/events/latency_info.h"
 
 #include <algorithm>
 #include <string>
 
 #include "base/json/json_writer.h"
@@ skipping 285 matching lines @@
           trace_name = std::string("Latency::") + trace_name_str;
       }
 
       TRACE_EVENT_COPY_ASYNC_BEGIN_WITH_TIMESTAMP0(
           "benchmark,latencyInfo",
           trace_name.c_str(),
           TRACE_ID_DONT_MANGLE(trace_id),
           ts);
     }
 
+    TRACE_EVENT_WITH_FLOW0("toplevel", "LatencyInfo::AddLatencyNumberWithTimestampImpl",
+                           TRACE_ID_DONT_MANGLE(trace_id),
+                           TRACE_EVENT_FLAG_FLOW_OUT);
     TRACE_EVENT_FLOW_BEGIN1(
         "input,benchmark", "LatencyInfo.Flow", TRACE_ID_DONT_MANGLE(trace_id),
         "trace_id", trace_id);
   }
 
   LatencyMap::key_type key = std::make_pair(component, id);
   LatencyMap::iterator it = latency_components.find(key);
   if (it == latency_components.end()) {
     LatencyComponent info = {component_sequence_number, time, event_count};
     latency_components[key] = info;
@@ skipping 16 matching lines @@
     CHECK(!terminated);
     terminated = true;
 
     if (*benchmark_enabled) {
       TRACE_EVENT_COPY_ASYNC_END1("benchmark,latencyInfo",
                                   trace_name.c_str(),
                                   TRACE_ID_DONT_MANGLE(trace_id),
                                   "data", AsTraceableData(*this));
     }
 
+    TRACE_EVENT_WITH_FLOW0("toplevel", "LatencyInfo::AddLatencyNumberWithTimestampImpl",
+                           TRACE_ID_DONT_MANGLE(trace_id),
+                           TRACE_EVENT_FLAG_FLOW_IN);
     TRACE_EVENT_FLOW_END_BIND_TO_ENCLOSING0(
         "input,benchmark", "LatencyInfo.Flow", TRACE_ID_DONT_MANGLE(trace_id));
   }
 }
 
 bool LatencyInfo::FindLatency(LatencyComponentType type,
                               int64 id,
                               LatencyComponent* output) const {
   LatencyMap::const_iterator it = latency_components.find(
       std::make_pair(type, id));
@@ skipping 15 matching lines @@
       it++;
     }
   }
 }
 
 void LatencyInfo::Clear() {
   latency_components.clear();
 }
 
 }  // namespace ui