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

webrtc/modules/video_coding/BUILD.gn

 # Copyright (c) 2014 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.
 
 import("../../build/webrtc.gni")
 
@@ skipping 37 matching lines @@
     "media_opt_util.h",
     "media_optimization.cc",
     "media_optimization.h",
     "nack_fec_tables.h",
     "nack_module.cc",
     "nack_module.h",
     "packet.cc",
     "packet.h",
     "packet_buffer.cc",
     "packet_buffer.h",
-    "percentile_filter.cc",
-    "percentile_filter.h",
     "protection_bitrate_calculator.cc",
     "protection_bitrate_calculator.h",
     "receiver.cc",
     "receiver.h",
     "rtp_frame_reference_finder.cc",
     "rtp_frame_reference_finder.h",
     "rtt_filter.cc",
     "rtt_filter.h",
     "session_info.cc",
     "session_info.h",
@@ skipping 199 matching lines @@
     if (!build_with_chromium && is_clang) {
       # Suppress warnings from the Chromium Clang plugin (bugs.webrtc.org/163).
       suppressed_configs += [ "//build/config/clang:find_bad_constructs" ]
     }
 
     deps = [
       "../../test:test_support",
     ]
   }
 }