Bug 1317946: allow receiving zero size UDP messages. r=schien

MozReview-Commit-ID: B8B1yDOPi3h

--HG--
extra : rebase_source : a0f87bc33584a24a148c0b7aea182da71f7ffdfb

netwerk/base/nsUDPSocket.cpp

@@ -472,12 +472,6 @@ nsUDPSocket::OnSocketReady(PRFileDesc *fd, int16_t outFlags)
   // support the maximum size of jumbo frames
   char buff[9216];
   count = PR_RecvFrom(mFD, buff, sizeof(buff), 0, &prClientAddr, PR_INTERVAL_NO_WAIT);
-
-  if (count < 1) {
-    NS_WARNING("error of recvfrom on UDP socket");
-    mCondition = NS_ERROR_UNEXPECTED;
-    return;
-  }
   mByteReadCount += count;
 
   FallibleTArray<uint8_t> data;