Use CopyOnWriteBuffer instead of Buffer to avoid unnecessary copies.

webrtc/api/java/jni/peerconnection_jni.cc

Index: webrtc/api/java/jni/peerconnection_jni.cc
diff --git a/webrtc/api/java/jni/peerconnection_jni.cc b/webrtc/api/java/jni/peerconnection_jni.cc
index 7a95737c9ab17c0353fb7fc5c0fff25f998bc8ad..8e259051d548590a660c8e575b1fa940bd16a120 100644
--- a/webrtc/api/java/jni/peerconnection_jni.cc
+++ b/webrtc/api/java/jni/peerconnection_jni.cc
@@ -851,7 +851,7 @@ JOW(jboolean, DataChannel_sendNative)(JNIEnv* jni, jobject j_dc,
                                       jbyteArray data, jboolean binary) {
   jbyte* bytes = jni->GetByteArrayElements(data, NULL);
   bool ret = ExtractNativeDC(jni, j_dc)->Send(DataBuffer(
-      rtc::Buffer(bytes, jni->GetArrayLength(data)),
+      rtc::CopyOnWriteBuffer(bytes, jni->GetArrayLength(data)),
       binary));
   jni->ReleaseByteArrayElements(data, bytes, JNI_ABORT);
   return ret;