Moving webrtc/stats/ into webrtc/api/ to resolve a circular dependency

webrtc/api/BUILD.gn

 # 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.
 
 import("../build/webrtc.gni")
 if (is_android) {
@@ skipping 66 matching lines @@
     "peerconnection.cc",
     "peerconnection.h",
     "peerconnectionfactory.cc",
     "peerconnectionfactory.h",
     "peerconnectionfactoryproxy.h",
     "peerconnectioninterface.h",
     "peerconnectionproxy.h",
     "proxy.h",
     "remoteaudiosource.cc",
     "remoteaudiosource.h",
+    "rtcstats.cc",
     "rtcstats.h",
+    "rtcstats_objects.cc",
     "rtcstats_objects.h",
+    "rtcstatscollector.cc",
+    "rtcstatscollector.h",
+    "rtcstatsreport.cc",
     "rtcstatsreport.h",
     "rtpparameters.h",
     "rtpreceiver.cc",
     "rtpreceiver.h",
     "rtpreceiverinterface.h",
     "rtpsender.cc",
     "rtpsender.h",
     "rtpsenderinterface.h",
     "sctputils.cc",
     "sctputils.h",
@@ skipping 230 matching lines @@
       "fakemetricsobserver.h",
       "jsepsessiondescription_unittest.cc",
       "localaudiosource_unittest.cc",
       "mediaconstraintsinterface_unittest.cc",
       "mediastream_unittest.cc",
       "peerconnection_unittest.cc",
       "peerconnectionendtoend_unittest.cc",
       "peerconnectionfactory_unittest.cc",
       "peerconnectioninterface_unittest.cc",
       "proxy_unittest.cc",
+      "rtcstats_unittest.cc",
+      "rtcstatscollector_unittest.cc",
+      "rtcstatsreport_unittest.cc",
       "rtpsenderreceiver_unittest.cc",
       "statscollector_unittest.cc",
       "test/fakeaudiocapturemodule.cc",
       "test/fakeaudiocapturemodule.h",
       "test/fakeaudiocapturemodule_unittest.cc",
       "test/fakeconstraints.h",
       "test/fakedatachannelprovider.h",
       "test/fakeperiodicvideocapturer.h",
       "test/fakertccertificategenerator.h",
       "test/fakevideotrackrenderer.h",
@@ skipping 97 matching lines @@
 
       shared_libraries = [ ":libjingle_peerconnection_so" ]
     }
 
     android_resources("libjingle_peerconnection_android_unittest_resources") {
       resource_dirs = [ "androidtests/res" ]
       custom_package = "org.webrtc"
     }
   }
 }