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

webrtc/api/api.gyp

 # Copyright (c) 2015 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.
 
 {
   'includes': [ '../build/common.gypi', ],
@@ skipping 16 matching lines @@
         {
           'target_name': 'libjingle_peerconnection_jni',
           'type': 'static_library',
           'dependencies': [
             '<(webrtc_root)/system_wrappers/system_wrappers.gyp:field_trial_default',
             'libjingle_peerconnection',
           ],
           'sources': [
             'androidvideocapturer.cc',
             'androidvideocapturer.h',
+            'java/jni/androidhistograms_jni.cc',
             'java/jni/androidmediacodeccommon.h',
             'java/jni/androidmediadecoder_jni.cc',
             'java/jni/androidmediadecoder_jni.h',
             'java/jni/androidmediaencoder_jni.cc',
             'java/jni/androidmediaencoder_jni.h',
             'java/jni/androidnetworkmonitor_jni.cc',
             'java/jni/androidnetworkmonitor_jni.h',
             'java/jni/androidvideocapturer_jni.cc',
             'java/jni/androidvideocapturer_jni.h',
             'java/jni/surfacetexturehelper_jni.cc',
@@ skipping 190 matching lines @@
               'AdditionalOptions': [
                 '-Wno-sign-compare',
               ],
             },
           },
         }],
       ],
     },  # target libjingle_peerconnection
   ],  # targets
 }