Kills TraceTicks, which was functionally the same as TimeTicks

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 226 matching lines @@
       // originally created, e.g. the timestamp of its ORIGINAL/UI_COMPONENT,
       // not when we actually issue the ASYNC_BEGIN trace event.
       LatencyComponent begin_component;
       int64 ts = 0;
       if (FindLatency(INPUT_EVENT_LATENCY_ORIGINAL_COMPONENT,
                       0,
                       &begin_component) ||
           FindLatency(INPUT_EVENT_LATENCY_UI_COMPONENT,
                       0,
                       &begin_component)) {
-        // The timestamp stored in ORIGINAL/UI_COMPONENT is using clock
-        // CLOCK_MONOTONIC while TRACE_EVENT_ASYNC_BEGIN_WITH_TIMESTAMP0
-        // expects timestamp using CLOCK_MONOTONIC or CLOCK_SYSTEM_TRACE (on
-        // CrOS). So we need to adjust the diff between in CLOCK_MONOTONIC and
-        // CLOCK_SYSTEM_TRACE. Note that the diff is drifting overtime so we
-        // can't use a static value.
-        base::TimeDelta diff = (base::TimeTicks::Now() - base::TimeTicks()) -
-            (base::TraceTicks::Now() - base::TraceTicks());
-        ts = (begin_component.event_time - diff).ToInternalValue();
+        ts = begin_component.event_time.ToInternalValue();
       } else {
-        ts = base::TraceTicks::Now().ToInternalValue();
+        ts = base::TimeTicks::Now().ToInternalValue();
       }
 
       if (trace_name_str) {
         if (IsInputLatencyBeginComponent(component))
           trace_name_ = std::string("InputLatency::") + trace_name_str;
         else
           trace_name_ = std::string("Latency::") + trace_name_str;
       }
 
       TRACE_EVENT_COPY_ASYNC_BEGIN_WITH_TIMESTAMP0(
@@ skipping 113 matching lines @@
 }
 
 bool LatencyInfo::AddCoalescedEventTimestamp(double timestamp) {
   if (coalesced_events_size_ >= kMaxCoalescedEventTimestamps)
     return false;
   timestamps_of_coalesced_events_[coalesced_events_size_++] = timestamp;
   return true;
 }
 
 }  // namespace ui