Update from https://crrev.com/312398

cc/debug/frame_timing_tracker.cc

+// Copyright 2015 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/debug/frame_timing_tracker.h"
+
+#include <algorithm>
+#include <limits>
+
+#include "base/metrics/histogram.h"
+#include "cc/trees/proxy.h"
+
+namespace cc {
+
+FrameTimingTracker::CompositeTimingEvent::CompositeTimingEvent(
+    int _frame_id,
+    base::TimeTicks _timestamp)
+    : frame_id(_frame_id), timestamp(_timestamp) {
+}
+
+FrameTimingTracker::CompositeTimingEvent::~CompositeTimingEvent() {
+}
+
+// static
+scoped_ptr<FrameTimingTracker> FrameTimingTracker::Create() {
+  return make_scoped_ptr(new FrameTimingTracker);
+}
+
+FrameTimingTracker::FrameTimingTracker() {
+}
+
+FrameTimingTracker::~FrameTimingTracker() {
+}
+
+void FrameTimingTracker::SaveTimeStamps(
+    base::TimeTicks timestamp,
+    const std::vector<FrameAndRectIds>& frame_ids) {
+  if (!composite_events_)
+    composite_events_.reset(new CompositeTimingSet);
+  for (const auto& pair : frame_ids)
+    (*composite_events_)[pair.second].push_back(
+        CompositeTimingEvent(pair.first, timestamp));
+}
+
+scoped_ptr<FrameTimingTracker::CompositeTimingSet>
+FrameTimingTracker::GroupCountsByRectId() {
+  if (!composite_events_)
+    return make_scoped_ptr(new CompositeTimingSet);
+  scoped_ptr<CompositeTimingSet> composite_info(new CompositeTimingSet);
+  for (auto& infos : *composite_events_)
+    std::sort(
+        infos.second.begin(), infos.second.end(),
+        [](const CompositeTimingEvent& lhs, const CompositeTimingEvent& rhs) {
+          return lhs.timestamp < rhs.timestamp;
+        });
+  return composite_events_.Pass();
+}
+
+}  // namespace cc