Revert of Make the default ctor of rtc::Thread, protected

webrtc/rtc_base/physicalsocketserver_unittest.cc

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 592 matching lines @@
 TEST_F(PosixSignalDeliveryTest, SignalOnDifferentThread) {
   ss_->SetPosixSignalHandler(SIGTERM, &RecordSignal);
   // Mask out SIGTERM so that it can't be delivered to this thread.
   sigset_t mask;
   sigemptyset(&mask);
   sigaddset(&mask, SIGTERM);
   EXPECT_EQ(0, pthread_sigmask(SIG_SETMASK, &mask, nullptr));
   // Start a new thread that raises it. It will have to be delivered to that
   // thread. Our implementation should safely handle it and dispatch
   // RecordSignal() on this thread.
-  std::unique_ptr<Thread> thread(Thread::CreateWithSocketServer());
+  std::unique_ptr<Thread> thread(new Thread());
   std::unique_ptr<RaiseSigTermRunnable> runnable(new RaiseSigTermRunnable());
   thread->Start(runnable.get());
   EXPECT_TRUE(ss_->Wait(1500, true));
   EXPECT_TRUE(ExpectSignal(SIGTERM));
   EXPECT_EQ(Thread::Current(), signaled_thread_);
   EXPECT_TRUE(ExpectNone());
 }
 
 #endif
 
 }  // namespace rtc