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

webrtc/sdk/android/src/jni/classreferenceholder.h

Index: webrtc/sdk/android/src/jni/classreferenceholder.h
diff --git a/webrtc/sdk/android/src/jni/classreferenceholder.h b/webrtc/sdk/android/src/jni/classreferenceholder.h
index 4859bcfb0d227ffc0bfebbcd153dbe8530db99d3..0d4ccc44a89ba26dfa0a1263cdcb0a742831ff5f 100644
--- a/webrtc/sdk/android/src/jni/classreferenceholder.h
+++ b/webrtc/sdk/android/src/jni/classreferenceholder.h
@@ -31,11 +31,6 @@ void FreeGlobalClassReferenceHolder();
 // process.
 jclass FindClass(JNIEnv* jni, const char* name);
 
-// Convenience macro defining JNI-accessible methods in the org.webrtc package.
-// Eliminates unnecessary boilerplate and line-wraps, reducing visual clutter.
-#define JOW(rettype, name) \
-  extern "C" JNIEXPORT rettype JNICALL Java_org_webrtc_##name
-
 }  // namespace webrtc_jni
 
 #endif  // WEBRTC_SDK_ANDROID_SRC_JNI_CLASSREFERENCEHOLDER_H_