Added missing level controller unittest to the modules/BUILD.gn build file

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 387 matching lines @@
         "audio_processing:audioproc_unittest_proto",
       ]
       sources += [
         "audio_processing/audio_processing_impl_locking_unittest.cc",
         "audio_processing/audio_processing_impl_unittest.cc",
         "audio_processing/audio_processing_unittest.cc",
         "audio_processing/echo_cancellation_bit_exact_unittest.cc",
         "audio_processing/echo_control_mobile_unittest.cc",
         "audio_processing/gain_control_unittest.cc",
         "audio_processing/high_pass_filter_unittest.cc",
+        "audio_processing/level_controller/level_controller_unittest.cc",
         "audio_processing/level_estimator_unittest.cc",
         "audio_processing/noise_suppression_unittest.cc",
         "audio_processing/test/bitexactness_tools.cc",
         "audio_processing/test/bitexactness_tools.h",
         "audio_processing/test/debug_dump_replayer.cc",
         "audio_processing/test/debug_dump_replayer.h",
         "audio_processing/test/debug_dump_test.cc",
         "audio_processing/test/test_utils.h",
         "audio_processing/voice_detection_unittest.cc",
       ]
@@ skipping 205 matching lines @@
         "audio_device/ios/objc/RTCAudioSessionTest.mm",
         "video_coding/codecs/h264/h264_video_toolbox_nalu_unittest.cc",
       ]
 
       ldflags = [ "-ObjC" ]
 
       # TODO(kjellander): Mac bundle files.
     }
   }
 }