Relanding: Break peerconnection_jni.cc into multiple files, in "pc" directory.

webrtc/sdk/android/src/jni/pc/rtcstatscollectorcallbackwrapper.h

 /*
  *  Copyright 2017 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.
  */
 
-#ifndef WEBRTC_SDK_ANDROID_SRC_JNI_RTCSTATSCOLLECTORCALLBACKWRAPPER_H_
-#define WEBRTC_SDK_ANDROID_SRC_JNI_RTCSTATSCOLLECTORCALLBACKWRAPPER_H_
+#ifndef WEBRTC_SDK_ANDROID_SRC_JNI_PC_RTCSTATSCOLLECTORCALLBACKWRAPPER_H_
+#define WEBRTC_SDK_ANDROID_SRC_JNI_PC_RTCSTATSCOLLECTORCALLBACKWRAPPER_H_
 
 #include <jni.h>
 
 #include "webrtc/api/peerconnectioninterface.h"
 #include "webrtc/sdk/android/src/jni/jni_helpers.h"
 
 namespace webrtc_jni {
 
 // Adapter for a Java RTCStatsCollectorCallback presenting a C++
 // RTCStatsCollectorCallback and dispatching the callback from C++ back to
@@ skipping 32 matching lines @@
   const jmethodID j_long_ctor_;
   const jclass j_big_integer_class_;
   const jmethodID j_big_integer_ctor_;
   const jclass j_double_class_;
   const jmethodID j_double_ctor_;
   const jclass j_string_class_;
 };
 
 }  // namespace webrtc_jni
 
-#endif  // WEBRTC_SDK_ANDROID_SRC_JNI_RTCSTATSCOLLECTORCALLBACKWRAPPER_H_
+#endif  // WEBRTC_SDK_ANDROID_SRC_JNI_PC_RTCSTATSCOLLECTORCALLBACKWRAPPER_H_