workaround for mac kernel bug

ipc/ipc_channel_posix.h

Index: ipc/ipc_channel_posix.h
diff --git a/ipc/ipc_channel_posix.h b/ipc/ipc_channel_posix.h
index 645a1303713116f188b037c5f537bee272444607..1e587c13eb0d02e8737db4d6c088659356656e3e 100644
--- a/ipc/ipc_channel_posix.h
+++ b/ipc/ipc_channel_posix.h
@@ -10,6 +10,7 @@
 #include <sys/socket.h>  // for CMSG macros
 
 #include <queue>
+#include <set>
 #include <string>
 #include <vector>
 
@@ -80,6 +81,8 @@ class Channel::ChannelImpl : public internal::ChannelReader,
   void ClosePipeOnError();
   int GetHelloMessageProcId();
   void QueueHelloMessage();
+  void CloseFileDescriptors(Message* msg);
+  void QueueCloseFDMessage(int fd, int hops);
 
   // ChannelReader implementation.
   virtual ReadState ReadData(char* buffer,
@@ -87,7 +90,7 @@ class Channel::ChannelImpl : public internal::ChannelReader,
                              int* bytes_read) OVERRIDE;
   virtual bool WillDispatchInputMessage(Message* msg) OVERRIDE;
   virtual bool DidEmptyInputBuffers() OVERRIDE;
-  virtual void HandleHelloMessage(const Message& msg) OVERRIDE;
+  virtual void HandleInternalMessage(const Message& msg) OVERRIDE;
 
 #if defined(IPC_USES_READWRITE)
   // Reads the next message from the fd_pipe_ and appends them to the
@@ -184,6 +187,13 @@ class Channel::ChannelImpl : public internal::ChannelReader,
   // implementation!
   std::vector<int> input_fds_;
 
+#if defined(OS_MACOSX)
+  // On OSX, sent FDs must not be closed until we get an ack.
+  // Keep track of sent FDs here to make sure the remote is not
+  // trying to bamboozle us.
+  std::set<int> fds_to_close_;
+#endif
+
   // True if we are responsible for unlinking the unix domain socket file.
   bool must_unlink_;