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

webrtc/modules/video_coding/codec_timer.cc

 /*
  *  Copyright (c) 2011 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.
  */
 
@@ skipping 16 matching lines @@
     : ignored_sample_count_(0), filter_(kPercentile) {}
 
 void VCMCodecTimer::AddTiming(int64_t decode_time_ms, int64_t now_ms) {
   // Ignore the first |kIgnoredSampleCount| samples.
   if (ignored_sample_count_ < kIgnoredSampleCount) {
     ++ignored_sample_count_;
     return;
   }
 
   // Insert new decode time value.
-  filter_.Insert(decode_time_ms);
+  filter_.Push(decode_time_ms);
   history_.emplace(decode_time_ms, now_ms);
 
   // Pop old decode time values.
   while (!history_.empty() &&
          now_ms - history_.front().sample_time_ms > kTimeLimitMs) {
-    filter_.Erase(history_.front().decode_time_ms);
+    filter_.Pop();
     history_.pop();
   }
 }
 
 // Get the 95th percentile observed decode time within a time window.
 int64_t VCMCodecTimer::RequiredDecodeTimeMs() const {
   return filter_.GetPercentileValue();
 }
 
 VCMCodecTimer::Sample::Sample(int64_t decode_time_ms, int64_t sample_time_ms)
     : decode_time_ms(decode_time_ms), sample_time_ms(sample_time_ms) {}
 
 }  // namespace webrtc