Add ReadIfReady() for tcp_socket_win

net/socket/ssl_client_socket_unittest.cc

Index: net/socket/ssl_client_socket_unittest.cc
diff --git a/net/socket/ssl_client_socket_unittest.cc b/net/socket/ssl_client_socket_unittest.cc
index bed7355c07a5e30eb365a69bf64279170863d4f1..63fce1a13ee41492457ab6ab15bc1ff1d8ac54ab 100644
--- a/net/socket/ssl_client_socket_unittest.cc
+++ b/net/socket/ssl_client_socket_unittest.cc
@@ -3779,14 +3779,7 @@ TEST_P(SSLClientSocketReadTest, DumpMemoryStats) {
   StreamSocket::SocketMemoryStats stats2;
   sock_->DumpMemoryStats(&stats2);
 
-  bool buffer_released = false;
   if (read_if_ready_enabled()) {
-// TODO(xunjieli): https://crbug.com/690915. Implement for windows.
-#if defined(OS_POSIX)
-    buffer_released = true;
-#endif
-  }
-  if (buffer_released) {
     EXPECT_EQ(0u, stats2.buffer_size);
     EXPECT_EQ(stats.cert_size, stats2.total_size);
   } else {