Templatize percentile_filter.h and move it to base/analytics.

webrtc/modules/video_coding/percentile_filter.cc

Index: webrtc/modules/video_coding/percentile_filter.cc
diff --git a/webrtc/modules/video_coding/percentile_filter.cc b/webrtc/modules/video_coding/percentile_filter.cc
deleted file mode 100644
index 6495567540961c86a721b58de9ba99a51694973e..0000000000000000000000000000000000000000
--- a/webrtc/modules/video_coding/percentile_filter.cc
+++ /dev/null
@@ -1,70 +0,0 @@
-/*
- *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
- *
- *  Use of this source code is governed by a BSD-style license
- *  that can be found in the LICENSE file in the root of the source
- *  tree. An additional intellectual property rights grant can be found
- *  in the file PATENTS.  All contributing project authors may
- *  be found in the AUTHORS file in the root of the source tree.
- */
-
-#include "webrtc/modules/video_coding/percentile_filter.h"
-
-#include <iterator>
-
-#include "webrtc/base/checks.h"
-
-namespace webrtc {
-
-PercentileFilter::PercentileFilter(float percentile)
-    : percentile_(percentile),
-      percentile_it_(set_.begin()),
-      percentile_index_(0) {
-  RTC_CHECK_GE(percentile, 0.0f);
-  RTC_CHECK_LE(percentile, 1.0f);
-}
-
-void PercentileFilter::Insert(const int64_t& value) {
-  // Insert element at the upper bound.
-  set_.insert(value);
-  if (set_.size() == 1u) {
-    // First element inserted - initialize percentile iterator and index.
-    percentile_it_ = set_.begin();
-    percentile_index_ = 0;
-  } else if (value < *percentile_it_) {
-    // If new element is before us, increment |percentile_index_|.
-    ++percentile_index_;
-  }
-  UpdatePercentileIterator();
-}
-
-void PercentileFilter::Erase(const int64_t& value) {
-  std::multiset<int64_t>::const_iterator it = set_.lower_bound(value);
-  // Ignore erase operation if the element is not present in the current set.
-  if (it == set_.end() || *it != value)
-    return;
-  if (it == percentile_it_) {
-    // If same iterator, update to the following element. Index is not affected.
-    percentile_it_ = set_.erase(it);
-  } else {
-    set_.erase(it);
-    // If erased element was before us, decrement |percentile_index_|.
-    if (value <= *percentile_it_)
-      --percentile_index_;
-  }
-  UpdatePercentileIterator();
-}
-
-void PercentileFilter::UpdatePercentileIterator() {
-  if (set_.empty())
-    return;
-  const int64_t index = static_cast<int64_t>(percentile_ * (set_.size() - 1));
-  std::advance(percentile_it_, index - percentile_index_);
-  percentile_index_ = index;
-}
-
-int64_t PercentileFilter::GetPercentileValue() const {
-  return set_.empty() ? 0 : *percentile_it_;
-}
-
-}  // namespace webrtc