IPC: Delete thread-safe send support

ipc/ipc_channel_common.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "build/build_config.h"
 #include "ipc/ipc_channel.h"
 #include "ipc/ipc_channel_mojo.h"
 #include "mojo/public/cpp/system/message_pipe.h"
 
 namespace IPC {
@@ skipping 68 matching lines @@
 Channel::AssociatedInterfaceSupport* Channel::GetAssociatedInterfaceSupport() {
   return nullptr;
 }
 
 void Channel::Pause() { NOTREACHED(); }
 
 void Channel::Unpause(bool flush) { NOTREACHED(); }
 
 void Channel::Flush() { NOTREACHED(); }
 
-bool Channel::IsSendThreadSafe() const {
-  return false;
-}
-
 void Channel::OnSetAttachmentBrokerEndpoint() {
   CHECK(!did_start_connect_);
 }
 
 void Channel::WillConnect() {
   did_start_connect_ = true;
 }
 
 }  // namespace IPC