Remove MockRemoteBitrateObserver (unused)

webrtc/modules/remote_bitrate_estimator/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("../../webrtc.gni")
 
@@ skipping 128 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" ]
     }
   }
 
   rtc_source_set("remote_bitrate_estimator_unittests") {
     testonly = true
     sources = [
       "aimd_rate_control_unittest.cc",
-      "include/mock/mock_remote_bitrate_estimator.h",
       "include/mock/mock_remote_bitrate_observer.h",
       "inter_arrival_unittest.cc",
       "overuse_detector_unittest.cc",
       "remote_bitrate_estimator_abs_send_time_unittest.cc",
       "remote_bitrate_estimator_single_stream_unittest.cc",
       "remote_bitrate_estimator_unittest_helper.cc",
       "remote_bitrate_estimator_unittest_helper.h",
       "remote_estimator_proxy_unittest.cc",
       "send_time_history_unittest.cc",
       "test/bwe_test_framework_unittest.cc",
@@ skipping 49 matching lines @@
     }
 
     if (is_win) {
       cflags = [
         # TODO(kjellander): bugs.webrtc.org/261: Fix this warning.
         "/wd4373",  # virtual function override.
       ]
     }
   }
 }