[lldb] Remove GDBRemoteCommunication::ConnectLocally (#145293)

Originally added for reproducers, it is now only used for test code.

While we could make it a test helper, I think that after #145015 it is
simple enough to not be needed.

Also squeeze in a change to make ConnectionFileDescriptor accept a
unique_ptr<Socket>.

lldb/source/Host/posix/ConnectionFileDescriptorPosix.cpp

@@ -72,9 +72,11 @@ ConnectionFileDescriptor::ConnectionFileDescriptor(int fd, bool owns_fd)
   OpenCommandPipe();
 }
 
-ConnectionFileDescriptor::ConnectionFileDescriptor(Socket *socket)
-    : Connection(), m_pipe(), m_mutex(), m_shutting_down(false) {
-  InitializeSocket(socket);
+ConnectionFileDescriptor::ConnectionFileDescriptor(
+    std::unique_ptr<Socket> socket_up)
+    : m_shutting_down(false) {
+  m_uri = socket_up->GetRemoteConnectionURI();
+  m_io_sp = std::move(socket_up);
 }
 
 ConnectionFileDescriptor::~ConnectionFileDescriptor() {
@@ -796,8 +798,3 @@ ConnectionStatus ConnectionFileDescriptor::ConnectSerialPort(
 #endif // LLDB_ENABLE_POSIX
   llvm_unreachable("this function should be only called w/ LLDB_ENABLE_POSIX");
 }
-
-void ConnectionFileDescriptor::InitializeSocket(Socket *socket) {
-  m_io_sp.reset(socket);
-  m_uri = socket->GetRemoteConnectionURI();
-}

lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.cpp

@@ -1128,8 +1128,8 @@ Status GDBRemoteCommunication::StartDebugserverProcess(
     Socket *accepted_socket = nullptr;
     error = sock_up->Accept(/*timeout=*/std::nullopt, accepted_socket);
     if (accepted_socket) {
-      SetConnection(
-          std::make_unique<ConnectionFileDescriptor>(accepted_socket));
+      SetConnection(std::make_unique<ConnectionFileDescriptor>(
+          std::unique_ptr<Socket>(accepted_socket)));
     }
   }
 
@@ -1138,20 +1138,6 @@ Status GDBRemoteCommunication::StartDebugserverProcess(
 
 void GDBRemoteCommunication::DumpHistory(Stream &strm) { m_history.Dump(strm); }
 
-llvm::Error
-GDBRemoteCommunication::ConnectLocally(GDBRemoteCommunication &client,
-                                       GDBRemoteCommunication &server) {
-  llvm::Expected<Socket::Pair> pair = Socket::CreatePair();
-  if (!pair)
-    return pair.takeError();
-
-  client.SetConnection(
-      std::make_unique<ConnectionFileDescriptor>(pair->first.release()));
-  server.SetConnection(
-      std::make_unique<ConnectionFileDescriptor>(pair->second.release()));
-  return llvm::Error::success();
-}
-
 GDBRemoteCommunication::ScopedTimeout::ScopedTimeout(
     GDBRemoteCommunication &gdb_comm, std::chrono::seconds timeout)
     : m_gdb_comm(gdb_comm), m_saved_timeout(0), m_timeout_modified(false) {

lldb/source/Plugins/Process/gdb-remote/GDBRemoteCommunication.h

@@ -149,9 +149,6 @@ public:
 
   void DumpHistory(Stream &strm);
 
-  static llvm::Error ConnectLocally(GDBRemoteCommunication &client,
-                                    GDBRemoteCommunication &server);
-
   /// Expand GDB run-length encoding.
   static std::optional<std::string> ExpandRLE(std::string);