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

webrtc/modules/BUILD.gn

 # 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.
 
 import("../build/webrtc.gni")
 import("audio_coding/audio_coding.gni")
@@ skipping 484 matching lines @@
       "video_coding/codecs/vp8/simulcast_unittest.cc",
       "video_coding/codecs/vp8/simulcast_unittest.h",
       "video_coding/decoding_state_unittest.cc",
       "video_coding/frame_buffer2_unittest.cc",
       "video_coding/h264_sps_pps_tracker_unittest.cc",
       "video_coding/histogram_unittest.cc",
       "video_coding/include/mock/mock_vcm_callbacks.h",
       "video_coding/jitter_buffer_unittest.cc",
       "video_coding/jitter_estimator_tests.cc",
       "video_coding/nack_module_unittest.cc",
-      "video_coding/percentile_filter_unittest.cc",
       "video_coding/protection_bitrate_calculator_unittest.cc",
       "video_coding/receiver_unittest.cc",
       "video_coding/rtp_frame_reference_finder_unittest.cc",
       "video_coding/sequence_number_util_unittest.cc",
       "video_coding/session_info_unittest.cc",
       "video_coding/test/stream_generator.cc",
       "video_coding/test/stream_generator.h",
       "video_coding/timing_unittest.cc",
       "video_coding/utility/default_video_bitrate_allocator_unittest.cc",
       "video_coding/utility/frame_dropper_unittest.cc",
@@ skipping 234 matching lines @@
       "../test:test_common",
       "../test:test_support_main",
       "remote_bitrate_estimator:bwe_simulator_lib",
       "video_capture",
       "//testing/gmock",
       "//testing/gtest",
       "//third_party/gflags",
     ]
   }
 }