Revert of Move content's shell connections to the IO thread

content/public/common/connection_filter.h

-// Copyright 2016 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.
-
-#ifndef CONTENT_PUBLIC_COMMON_CONNECTION_FILTER_H_
-#define CONTENT_PUBLIC_COMMON_CONNECTION_FILTER_H_
-
-#include "content/common/content_export.h"
-
-namespace shell {
-class Connection;
-class Connector;
-}
-
-namespace content {
-
-// A ConnectionFilter may be used to conditionally expose interfaces on inbound
-// connections accepted by MojoShellConnection. ConnectionFilters are used
-// exclusively on the IO thread. See MojoShellConnection::AddConnectionFilter
-// for details.
-class CONTENT_EXPORT ConnectionFilter {
- public:
-  virtual ~ConnectionFilter() {}
-
-  // Called for every new connection accepted. Implementations may add
-  // interfaces to |connection|, in which case they should return |true|.
-  // |connector| is a corresponding outgoing Connector that may be used by any
-  // interfaces added to the connection. Note that references to |connector|
-  // must not be retained, but an owned copy may be obtained by calling
-  // |connector->Clone()|.
-  //
-  // If a ConnectionFilter is not interested in an incoming connection, it
-  // should return |false|.
-  virtual bool OnConnect(shell::Connection* connection,
-                         shell::Connector* connector) = 0;
-};
-
-}  // namespace content
-
-#endif  // CONTENT_PUBLIC_COMMON_CONNECTION_FILTER_H_