Android: Add common function for adding/releasing native reference

webrtc/sdk/android/BUILD.gn

 # Copyright (c) 2016 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("../../webrtc.gni")
 import("//build/config/android/config.gni")
@@ skipping 20 matching lines @@
       "-Wno-unused-variable",
     ]
   }
 }
 
 rtc_source_set("base_jni") {
   sources = [
     "src/jni/androidhistogram_jni.cc",
     "src/jni/classreferenceholder.cc",
     "src/jni/classreferenceholder.h",
+    "src/jni/jni_common.cc",
     "src/jni/jni_helpers.cc",
     "src/jni/jni_helpers.h",
     "src/jni/pc/audio_jni.h",
     "src/jni/pc/media_jni.h",
     "src/jni/pc/video_jni.h",
   ]
 
   deps = [
     "../../api:libjingle_peerconnection_api",
     "../../rtc_base:rtc_base",
@@ skipping 379 matching lines @@
     "src/java/org/webrtc/CameraCapturer.java",
     "src/java/org/webrtc/CameraSession.java",
     "src/java/org/webrtc/DynamicBitrateAdjuster.java",
     "src/java/org/webrtc/EglBase10.java",
     "src/java/org/webrtc/EglBase14.java",
     "src/java/org/webrtc/FramerateBitrateAdjuster.java",
     "src/java/org/webrtc/HardwareVideoDecoder.java",
     "src/java/org/webrtc/HardwareVideoEncoder.java",
     "src/java/org/webrtc/Histogram.java",
     "src/java/org/webrtc/I420BufferImpl.java",
+    "src/java/org/webrtc/JniCommon.java",
     "src/java/org/webrtc/MediaCodecUtils.java",
     "src/java/org/webrtc/NV12Buffer.java",
     "src/java/org/webrtc/NV21Buffer.java",
     "src/java/org/webrtc/TextureBufferImpl.java",
     "src/java/org/webrtc/VideoCodecType.java",
     "src/java/org/webrtc/VideoDecoderWrapperCallback.java",
     "src/java/org/webrtc/WrappedNativeI420Buffer.java",
     "src/java/org/webrtc/YuvConverter.java",
   ]
 
@@ skipping 56 matching lines @@
       "//third_party/android_support_test_runner:runner_java",
       "//third_party/junit",
     ]
 
     shared_libraries = [ "../../sdk/android:libjingle_peerconnection_so" ]
 
     # TODO(sakal): Fix build hooks crbug.com/webrtc/8148
     no_build_hooks = true
   }
 }