Send input event's LatencyInfo back from renderer to browser when acked

ui/base/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/base/latency_info.h"
 
 #include <algorithm>
 
 namespace ui {
 
 LatencyInfo::LatencyInfo() {
 }
 
 LatencyInfo::~LatencyInfo() {
 }
 
 void LatencyInfo::MergeWith(const LatencyInfo& other) {
   for (LatencyMap::const_iterator it = other.latency_components.begin();
        it != other.latency_components.end();
        ++it) {
     AddLatencyNumberWithTimestamp(it->first.first,
                                   it->first.second,
                                   it->second.sequence_number,
                                   it->second.event_time,
                                   it->second.event_count);
   }
 }
 
+void LatencyInfo::AddNewLatencyFrom(const LatencyInfo& other) {
+    for (LatencyMap::const_iterator it = other.latency_components.begin();
+         it != other.latency_components.end();
+         ++it) {
+      if (!FindLatency(it->first.first, it->first.second, NULL)) {
+        AddLatencyNumberWithTimestamp(it->first.first,
+                                      it->first.second,
+                                      it->second.sequence_number,
+                                      it->second.event_time,
+                                      it->second.event_count);
+      }
+    }
+}
+
 void LatencyInfo::AddLatencyNumber(LatencyComponentType component,
                                    int64 id,
                                    int64 component_sequence_number) {
   AddLatencyNumberWithTimestamp(component, id, component_sequence_number,
                                 base::TimeTicks::HighResNow(), 1);
 }
 
 void LatencyInfo::AddLatencyNumberWithTimestamp(LatencyComponentType component,
                                                 int64 id,
                                                 int64 component_sequence_number,
@@ skipping 29 matching lines @@
   if (output)
     *output = it->second;
   return true;
 }
 
 void LatencyInfo::Clear() {
   latency_components.clear();
 }
 
 }  // namespace ui