Read recv timestamps from socket (posix only).

webrtc/base/macasyncsocket.cc

Index: webrtc/base/macasyncsocket.cc
diff --git a/webrtc/base/macasyncsocket.cc b/webrtc/base/macasyncsocket.cc
index 8f811ea8b668ed5d8bbab7acc51a61f18cd1feed..9f38c2937ca5388fdbe21df2dfd9dd2ab2d8b32a 100644
--- a/webrtc/base/macasyncsocket.cc
+++ b/webrtc/base/macasyncsocket.cc
@@ -188,7 +188,10 @@ int MacAsyncSocket::SendTo(const void* buffer, size_t length,
 }
 
 // Read data received from the remote end we're connected to.
-int MacAsyncSocket::Recv(void* buffer, size_t length) {
+int MacAsyncSocket::Recv(void* buffer, size_t length, int64_t* timestamp) {
+  if (timestamp) {
+    *timestamp = -1;
+  }
   int received = ::recv(native_socket_, reinterpret_cast<char*>(buffer),
                         length, 0);
   if (received == SOCKET_ERROR) error_ = errno;
@@ -199,8 +202,13 @@ int MacAsyncSocket::Recv(void* buffer, size_t length) {
 }
 
 // Read data received from any remote party
-int MacAsyncSocket::RecvFrom(void* buffer, size_t length,
-                             SocketAddress* out_addr) {
+int MacAsyncSocket::RecvFrom(void* buffer,
+                             size_t length,
+                             SocketAddress* out_addr,
+                             int64_t* timestamp) {
+  if (timestamp) {
+    *timestamp = -1;
+  }
   sockaddr_storage saddr;
   socklen_t addr_len = sizeof(saddr);
   int received = ::recvfrom(native_socket_, reinterpret_cast<char*>(buffer),