Wait properly for renderer crashes

ipc/ipc_channel.h

Index: ipc/ipc_channel.h
diff --git a/ipc/ipc_channel.h b/ipc/ipc_channel.h
index 8bb35c4538972d2166d07647cf6d231a2ed06a48..718f2b393d5acdee3e606b899460e31a99ddb027 100644
--- a/ipc/ipc_channel.h
+++ b/ipc/ipc_channel.h
@@ -146,8 +146,14 @@ class IPC_EXPORT Channel : public Message::Sender {
   // On POSIX an IPC::Channel wraps a socketpair(), this method returns the
   // FD # for the client end of the socket.
   // This method may only be called on the server side of a channel.
+  // This method can be called on any thread.
   int GetClientFileDescriptor() const;
 
+  // Same as GetClientFileDescriptor, but transfers the ownership of the
+  // file descriptor to the caller.
+  // This method can be called on any thread.
+  int TakeClientFileDescriptor();
+
   // On POSIX an IPC::Channel can either wrap an established socket, or it
   // can wrap a socket that is listening for connections. Currently an
   // IPC::Channel that listens for connections can only accept one connection