Remove some LatencyInfo merging code path

cc/base/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/base/latency_info_swap_promise.h"
 
 #include "base/logging.h"
 
 namespace {
   ui::LatencyComponentType DidNotSwapReasonToLatencyComponentType(
@@ skipping 16 matching lines @@
 
 LatencyInfoSwapPromise::LatencyInfoSwapPromise(const ui::LatencyInfo& latency)
     : latency_(latency) {
 }
 
 LatencyInfoSwapPromise::~LatencyInfoSwapPromise() {
 }
 
 void LatencyInfoSwapPromise::DidSwap(CompositorFrameMetadata* metadata) {
   DCHECK(!latency_.terminated);
-  // TODO(miletus): Append the |latency_| into metadata's LatencyInfo list
-  // once we remove LatencyInfo merge in GPU side.
-  metadata->latency_info.MergeWith(latency_);
+  metadata->latency_info.push_back(latency_);
 }
 
 void LatencyInfoSwapPromise::DidNotSwap(DidNotSwapReason reason) {
   latency_.AddLatencyNumber(DidNotSwapReasonToLatencyComponentType(reason),
                             0, 0);
   // TODO(miletus): Turn this back on once per-event LatencyInfo tracking
   // is enabled in GPU side.
   // DCHECK(latency_.terminated);
 }
 
 }  // namespace cc