Add a default implementation in metrics_default.cc of histograms methods in system_wrappers/interfac

webrtc/test/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): Convert the rest of the test.gyp targets and put here.
 
@@ skipping 16 matching lines @@
   deps = [
     "..:webrtc_common",
     "../system_wrappers",
     "../system_wrappers:field_trial_default",
   ]
 
   configs += [ "..:common_config" ]
   public_configs = [ "..:common_inherited_config" ]
 }
 
-source_set("histogram") {
-  sources = [
-    "histogram.cc",
-    "histogram.h",
-  ]
-
-  deps = [
-    "..:webrtc_common",
-    "../system_wrappers",
-  ]
-
-  configs += [ "..:common_config" ]
-  public_configs = [ "..:common_inherited_config" ]
-}
-
 source_set("test_support") {
   testonly = true
 
   sources = [
     "testsupport/fileutils.cc",
     "testsupport/fileutils.h",
     "testsupport/frame_reader.cc",
     "testsupport/frame_reader.h",
     "testsupport/frame_writer.cc",
     "testsupport/frame_writer.h",
@@ skipping 31 matching lines @@
   testonly = true
 
   sources = [
     "run_all_unittests.cc",
     "test_suite.cc",
     "test_suite.h",
   ]
 
   deps = [
     ":field_trial",
-    ":histogram",
     ":test_support",
+    "../system_wrappers:metrics_default",
     "//testing/gmock",
     "//testing/gtest",
     "//third_party/gflags",
   ]
 
   configs += [ "..:common_config" ]
   public_configs = [ "..:common_inherited_config" ]
 }