Remove LatencyInfo::sequence_number. (May break metrics).

ui/latency/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/latency/latency_info.h"
 
 #include <stddef.h>
 
 #include <algorithm>
 #include <string>
@@ skipping 148 matching lines @@
   }
   return true;
 }
 
 void LatencyInfo::CopyLatencyFrom(const LatencyInfo& other,
                                   LatencyComponentType type) {
   for (const auto& lc : other.latency_components()) {
     if (lc.first.first == type) {
       AddLatencyNumberWithTimestamp(lc.first.first,
                                     lc.first.second,
-                                    lc.second.sequence_number,
                                     lc.second.event_time,
                                     lc.second.event_count);
     }
   }
 }
 
 void LatencyInfo::AddNewLatencyFrom(const LatencyInfo& other) {
   for (const auto& lc : other.latency_components()) {
     if (!FindLatency(lc.first.first, lc.first.second, NULL)) {
       AddLatencyNumberWithTimestamp(lc.first.first,
                                     lc.first.second,
-                                    lc.second.sequence_number,
                                     lc.second.event_time,
                                     lc.second.event_count);
     }
   }
 }
 
-void LatencyInfo::AddLatencyNumber(LatencyComponentType component,
-                                   int64_t id,
-                                   int64_t component_sequence_number) {
-  AddLatencyNumberWithTimestampImpl(component, id, component_sequence_number,
-                                    base::TimeTicks::Now(), 1, nullptr);
+void LatencyInfo::AddLatencyNumber(LatencyComponentType component, int64_t id) {
+  AddLatencyNumberWithTimestampImpl(component, id, base::TimeTicks::Now(), 1,
+                                    nullptr);
 }
 
 void LatencyInfo::AddLatencyNumberWithTraceName(
     LatencyComponentType component,
     int64_t id,
-    int64_t component_sequence_number,
     const char* trace_name_str) {
-  AddLatencyNumberWithTimestampImpl(component, id, component_sequence_number,
-                                    base::TimeTicks::Now(), 1, trace_name_str);
+  AddLatencyNumberWithTimestampImpl(component, id, base::TimeTicks::Now(), 1,
+                                    trace_name_str);
 }
 
 void LatencyInfo::AddLatencyNumberWithTimestamp(
     LatencyComponentType component,
     int64_t id,
-    int64_t component_sequence_number,
     base::TimeTicks time,
     uint32_t event_count) {
-  AddLatencyNumberWithTimestampImpl(component, id, component_sequence_number,
-                                    time, event_count, nullptr);
+  AddLatencyNumberWithTimestampImpl(component, id, time, event_count, nullptr);
 }
 
 void LatencyInfo::AddLatencyNumberWithTimestampImpl(
     LatencyComponentType component,
     int64_t id,
-    int64_t component_sequence_number,
     base::TimeTicks time,
     uint32_t event_count,
     const char* trace_name_str) {
   const unsigned char* latency_info_enabled =
       g_latency_info_enabled.Get().latency_info_enabled;
 
   if (IsBeginComponent(component)) {
+    static int global_trace_id = 0;

[tdresser, 2017/06/08 18:36:44]

Real change.

[dtapuska, 2017/06/09 15:15:35]

This is kind of scary because latency_info.cc could be instantiated in multiple
processes. Should the global_trace_id be started off with some type of seed?

[tdresser, 2017/06/29 19:04:38]

Dealt with in separate patch.

     // Should only ever add begin component once.
     CHECK_EQ(-1, trace_id_);
-    trace_id_ = component_sequence_number;
+    trace_id_ = global_trace_id++;  // TODO.

[tdresser, 2017/06/08 18:36:44]

I'm not super happy with this naming. Any thoughts?

[dtapuska, 2017/06/26 20:51:43]

global trace id isn't ideal because this is actually limited to this process id
and they are IPC'd.

 
     if (*latency_info_enabled) {
       // The timestamp for ASYNC_BEGIN trace event is used for drawing the
       // beginning of the trace event in trace viewer. For better visualization,
       // for an input event, we want to draw the beginning as when the event is
       // originally created, e.g. the timestamp of its ORIGINAL/UI_COMPONENT,
       // not when we actually issue the ASYNC_BEGIN trace event.
       LatencyComponent begin_component;
       base::TimeTicks ts;
       if (FindLatency(INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT,
@@ skipping 24 matching lines @@
     TRACE_EVENT_WITH_FLOW1("input,benchmark",
                            "LatencyInfo.Flow",
                            TRACE_ID_DONT_MANGLE(trace_id_),
                            TRACE_EVENT_FLAG_FLOW_OUT,
                            "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, time,
-                             time};
+    LatencyComponent info = {time, event_count, time, time};
     latency_components_[key] = info;
   } else {
-    it->second.sequence_number = std::max(component_sequence_number,
-                                          it->second.sequence_number);
     uint32_t new_count = event_count + it->second.event_count;
     if (event_count > 0 && new_count != 0) {
       // Do a weighted average, so that the new event_time is the average of
       // the times of events currently in this structure with the time passed
       // into this method.
       it->second.event_time += (time - it->second.event_time) * event_count /
           new_count;
       it->second.event_count = new_count;
       it->second.last_event_time = std::max(it->second.last_event_time, time);
     }
@@ skipping 22 matching lines @@
   std::unique_ptr<base::DictionaryValue> record_data(
       new base::DictionaryValue());
   for (const auto& lc : latency_components_) {
     std::unique_ptr<base::DictionaryValue> component_info(
         new base::DictionaryValue());
     component_info->SetDouble("comp_id", static_cast<double>(lc.first.second));
     component_info->SetDouble(
         "time",
         static_cast<double>(lc.second.event_time.ToInternalValue()));
     component_info->SetDouble("count", lc.second.event_count);
-    component_info->SetDouble("sequence_number",
-                              lc.second.sequence_number);
     record_data->Set(GetComponentName(lc.first.first),
                      std::move(component_info));
   }
   record_data->SetDouble("trace_id", static_cast<double>(trace_id_));
   return LatencyInfoTracedValue::FromValue(std::move(record_data));
 }
 
 bool LatencyInfo::FindLatency(LatencyComponentType type,
                               int64_t id,
                               LatencyComponent* output) const {
@@ skipping 24 matching lines @@
   LatencyMap::iterator it = latency_components_.begin();
   while (it != latency_components_.end()) {
     if (it->first.first == type)
       it = latency_components_.erase(it);
     else
       it++;
   }
 }
 
 }  // namespace ui