Move more Mojo bindings helpers out of internal namespace

mojo/public/cpp/bindings/lib/pipe_control_message_handler.h

-// Copyright 2015 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 MOJO_PUBLIC_CPP_BINDINGS_LIB_PIPE_CONTROL_MESSAGE_HANDLER_H_
-#define MOJO_PUBLIC_CPP_BINDINGS_LIB_PIPE_CONTROL_MESSAGE_HANDLER_H_
-
-#include "base/macros.h"
-#include "mojo/public/cpp/bindings/interface_id.h"
-#include "mojo/public/cpp/bindings/lib/serialization_context.h"
-#include "mojo/public/cpp/bindings/message.h"
-
-namespace mojo {
-namespace internal {
-
-class PipeControlMessageHandlerDelegate;
-
-// Handler for messages defined in pipe_control_messages.mojom.
-class PipeControlMessageHandler : public MessageReceiver {
- public:
-  explicit PipeControlMessageHandler(
-      PipeControlMessageHandlerDelegate* delegate);
-  ~PipeControlMessageHandler() override;
-
-  // Sets the description for this handler. Used only when reporting validation
-  // errors.
-  void SetDescription(const std::string& description);
-
-  // NOTE: |message| must have passed message header validation.
-  static bool IsPipeControlMessage(const Message* message);
-
-  // MessageReceiver implementation:
-
-  // NOTE: |message| must:
-  //   - have passed message header validation; and
-  //   - be a pipe control message (i.e., IsPipeControlMessage() returns true).
-  // If the method returns false, the message pipe should be closed.
-  bool Accept(Message* message) override;
-
- private:
-  // |message| must have passed message header validation.
-  bool Validate(Message* message);
-  bool RunOrClosePipe(Message* message);
-
-  std::string description_;
-  PipeControlMessageHandlerDelegate* const delegate_;
-  SerializationContext context_;
-
-  DISALLOW_COPY_AND_ASSIGN(PipeControlMessageHandler);
-};
-
-}  // namespace internal
-}  // namespace mojo
-
-#endif  // MOJO_PUBLIC_CPP_BINDINGS_LIB_PIPE_CONTROL_MESSAGE_HANDLER_H_