GN: Make audio_processing_unittests compile with rtc_enable_protobuf=false

webrtc/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.
 
 # TODO(kjellander): Rebase this to webrtc/build/common.gypi changes after r6330.
 
@@ skipping 353 matching lines @@
 
   rtc_test("rtc_unittests") {
     testonly = true
     deps = [
       "base:rtc_base_approved_unittests",
       "base:rtc_base_unittests",
       "base:rtc_numerics_unittests",
       "base:rtc_task_queue_unittests",
       "p2p:libstunprober_unittests",
       "p2p:rtc_p2p_unittests",
+      "system_wrappers:metrics_default",
     ]
 
     if (rtc_enable_protobuf) {
       deps += [ "logging:rtc_event_log_tests" ]
     }
 
     if (is_android) {
       deps += [ "//testing/android/native_test:native_test_support" ]
       shard_timeout = 900
     }
@@ skipping 115 matching lines @@
       ]
 
       deps = [
         "//base:base_java_test_support",
         "//webrtc/examples:AppRTCMobile_javalib",
         "//webrtc/sdk/android:libjingle_peerconnection_java",
       ]
     }
   }
 }