Remove 'mask' from SocketData, as it's not required.

runtime/bin/eventhandler_linux.h

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef BIN_EVENTHANDLER_LINUX_H_
 #define BIN_EVENTHANDLER_LINUX_H_
 
 #if !defined(BIN_EVENTHANDLER_H_)
 #error Do not include eventhandler_linux.h directly; use eventhandler.h instead.
 #endif
@@ skipping 13 matching lines @@
  public:
   intptr_t id;
   Dart_Port dart_port;
   int64_t data;
 };
 
 
 class SocketData {
  public:
   explicit SocketData(intptr_t fd)
-      : tracked_by_epoll_(false), fd_(fd), port_(0), mask_(0) {
+      : tracked_by_epoll_(false), fd_(fd), port_(0) {
     ASSERT(fd_ != -1);
   }
 
   void ShutdownRead() {
     shutdown(fd_, SHUT_RD);
   }
 
   void ShutdownWrite() {
     shutdown(fd_, SHUT_WR);
   }
 
   void Close() {
     port_ = 0;
-    mask_ = 0;
     close(fd_);
     fd_ = -1;
   }
 
-  bool IsListeningSocket() { return (mask_ & (1 << kListeningSocket)) != 0; }
-  bool IsPipe() { return (mask_ & (1 << kPipe)) != 0; }
-
-  void SetPortAndMask(Dart_Port port, intptr_t mask) {
+  void SetPort(Dart_Port port) {
     ASSERT(fd_ != -1);
     port_ = port;
-    mask_ = mask;
   }
 
   intptr_t fd() { return fd_; }
   Dart_Port port() { return port_; }
-  intptr_t mask() { return mask_; }
   bool tracked_by_epoll() { return tracked_by_epoll_; }
   void set_tracked_by_epoll(bool value) { tracked_by_epoll_ = value; }
 
  private:
   bool tracked_by_epoll_;
   intptr_t fd_;
   Dart_Port port_;
   intptr_t mask_;
 };
 
@@ skipping 25 matching lines @@
   bool shutdown_;
   int interrupt_fds_[2];
   int epoll_fd_;
   int timer_fd_;
 };
 
 }  // namespace bin
 }  // namespace dart
 
 #endif  // BIN_EVENTHANDLER_LINUX_H_