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

webrtc/api/api_tests.gyp

Index: webrtc/api/api_tests.gyp
diff --git a/webrtc/api/api_tests.gyp b/webrtc/api/api_tests.gyp
index f59eaec0f2ba421ab5c18d97c6cb6ac2e833eebb..7a3ea1ea7b6c9f6ff2d1b58b612fa1300d317524 100644
--- a/webrtc/api/api_tests.gyp
+++ b/webrtc/api/api_tests.gyp
@@ -100,6 +100,10 @@
             '<(DEPTH)/testing/android/native_test.gyp:native_test_native_code',
             '<(webrtc_root)/api/api.gyp:libjingle_peerconnection_jni',
           ],
+        }, {
+          'dependencies': [
+            '<(webrtc_root)/system_wrappers/system_wrappers.gyp:metrics_default',
+          ],
         }],
         ['OS=="win" and clang==1', {
           'msvs_settings': {