Revert of [cast_channel] Move cast_channel related files from //extensions to //components

extensions/browser/api/cast_channel/cast_transport.h

Index: extensions/browser/api/cast_channel/cast_transport.h
diff --git a/extensions/browser/api/cast_channel/cast_transport.h b/extensions/browser/api/cast_channel/cast_transport.h
new file mode 100644
index 0000000000000000000000000000000000000000..68769e14200ad7d533a8cd47cf9cd158b18f7e8c
--- /dev/null
+++ b/extensions/browser/api/cast_channel/cast_transport.h
@@ -0,0 +1,231 @@
+// 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.
+
+#ifndef EXTENSIONS_BROWSER_API_CAST_CHANNEL_CAST_TRANSPORT_H_
+#define EXTENSIONS_BROWSER_API_CAST_CHANNEL_CAST_TRANSPORT_H_
+
+#include <queue>
+#include <string>
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/sequence_checker.h"
+#include "base/threading/thread_checker.h"
+#include "components/cast_channel/cast_channel_enum.h"
+#include "extensions/browser/api/cast_channel/logger.h"
+#include "extensions/common/api/cast_channel/logging.pb.h"
+#include "net/base/completion_callback.h"
+#include "net/base/ip_endpoint.h"
+
+namespace net {
+class DrainableIOBuffer;
+class DrainableIOBuffer;
+class GrowableIOBuffer;
+class Socket;
+}  // namespace net
+
+namespace extensions {
+namespace api {
+namespace cast_channel {
+class CastMessage;
+class MessageFramer;
+
+class CastTransport {
+ public:
+  virtual ~CastTransport() {}
+
+  // Object to be informed of incoming messages and read errors.
+  class Delegate {
+   public:
+    using ChannelError = ::cast_channel::ChannelError;
+
+    virtual ~Delegate() {}
+
+    // Called once Transport is successfully initialized and started.
+    // Owned read delegates are Start()ed automatically.
+    virtual void Start() = 0;
+
+    // An error occurred on the channel.
+    // The caller is responsible for closing |socket| if an error occurred.
+    virtual void OnError(ChannelError error_state) = 0;
+
+    // A message was received on the channel.
+    virtual void OnMessage(const CastMessage& message) = 0;
+  };
+
+  // Sends a CastMessage to |socket_|.
+  // |message|: The message to send.
+  // |callback|: Callback to be invoked when the write operation has finished.
+  // Virtual for testing.
+  virtual void SendMessage(const CastMessage& message,
+                           const net::CompletionCallback& callback) = 0;
+
+  // Initializes the reading state machine and starts reading from the
+  // underlying socket.
+  // Virtual for testing.
+  virtual void Start() = 0;
+
+  // Changes the delegate for processing read events. Pending reads remain
+  // in-flight.
+  // Ownership of the pointee of |delegate| is assumed by the transport.
+  // Prior delegates are deleted automatically.
+  virtual void SetReadDelegate(std::unique_ptr<Delegate> delegate) = 0;
+};
+
+// Manager class for reading and writing messages to/from a socket.
+class CastTransportImpl : public CastTransport {
+ public:
+  using ChannelAuthType = ::cast_channel::ChannelAuthType;
+  using ChannelError = ::cast_channel::ChannelError;
+
+  // Adds a CastMessage read/write layer to a socket.
+  // Message read events are propagated to the owner via |read_delegate|.
+  // |vlog_prefix| sets the prefix used for all VLOGged output.
+  // |socket| and |logger| must all out-live the
+  // CastTransportImpl instance.
+  // |read_delegate| is owned by this CastTransportImpl object.
+  CastTransportImpl(net::Socket* socket,
+                    int channel_id,
+                    const net::IPEndPoint& ip_endpoint_,
+                    ChannelAuthType channel_auth_,
+                    scoped_refptr<Logger> logger);
+
+  ~CastTransportImpl() override;
+
+  // CastTransport interface.
+  void SendMessage(const CastMessage& message,
+                   const net::CompletionCallback& callback) override;
+  void Start() override;
+  void SetReadDelegate(std::unique_ptr<Delegate> delegate) override;
+
+ private:
+  // Internal write states.
+  enum WriteState {
+    WRITE_STATE_UNKNOWN,
+    WRITE_STATE_WRITE,
+    WRITE_STATE_WRITE_COMPLETE,
+    WRITE_STATE_DO_CALLBACK,
+    WRITE_STATE_HANDLE_ERROR,
+    WRITE_STATE_ERROR,
+    WRITE_STATE_IDLE,
+  };
+
+  // Internal read states.
+  enum ReadState {
+    READ_STATE_UNKNOWN,
+    READ_STATE_READ,
+    READ_STATE_READ_COMPLETE,
+    READ_STATE_DO_CALLBACK,
+    READ_STATE_HANDLE_ERROR,
+    READ_STATE_ERROR,
+  };
+
+  // Holds a message to be written to the socket. |callback| is invoked when the
+  // message is fully written or an error occurrs.
+  struct WriteRequest {
+    explicit WriteRequest(const std::string& namespace_,
+                          const std::string& payload,
+                          const net::CompletionCallback& callback);
+    WriteRequest(const WriteRequest& other);
+    ~WriteRequest();
+
+    // Namespace of the serialized message.
+    std::string message_namespace;
+    // Write completion callback, invoked when the operation has completed or
+    // failed.
+    net::CompletionCallback callback;
+    // Buffer with outgoing data.
+    scoped_refptr<net::DrainableIOBuffer> io_buffer;
+  };
+
+  static proto::ReadState ReadStateToProto(CastTransportImpl::ReadState state);
+  static proto::WriteState WriteStateToProto(
+      CastTransportImpl::WriteState state);
+  static proto::ErrorState ErrorStateToProto(ChannelError state);
+  static bool IsTerminalReadState(ReadState read_state);
+  static bool IsTerminalWriteState(WriteState write_state);
+
+  void SetReadState(ReadState read_state);
+  void SetWriteState(WriteState write_state);
+  void SetErrorState(ChannelError error_state);
+
+  // Terminates all in-flight write callbacks with error code ERR_FAILED.
+  void FlushWriteQueue();
+
+  // Main method that performs write flow state transitions.
+  void OnWriteResult(int result);
+
+  // Each of the below Do* method is executed in the corresponding
+  // write state. For example when write state is WRITE_STATE_WRITE_COMPLETE
+  // DowriteComplete is called, and so on.
+  int DoWrite();
+  int DoWriteComplete(int result);
+  int DoWriteCallback();
+  int DoWriteHandleError(int result);
+
+  // Main method that performs write flow state transitions.
+  void OnReadResult(int result);
+
+  // Each of the below Do* method is executed in the corresponding
+  // write state. For example when read state is READ_STATE_READ_COMPLETE
+  // DoReadComplete is called, and so on.
+  int DoRead();
+  int DoReadComplete(int result);
+  int DoReadCallback();
+  int DoReadHandleError(int result);
+
+  // Indicates that the transport object is started and may receive and send
+  // messages.
+  bool started_;
+
+  // Queue of pending writes. The message at the front of the queue is the one
+  // being written.
+  std::queue<WriteRequest> write_queue_;
+
+  // Buffer used for read operations. Reused for every read.
+  scoped_refptr<net::GrowableIOBuffer> read_buffer_;
+
+  // Constructs and parses the wire representation of message frames.
+  std::unique_ptr<MessageFramer> framer_;
+
+  // Last message received on the socket.
+  std::unique_ptr<CastMessage> current_message_;
+
+  // Socket used for I/O operations.
+  net::Socket* const socket_;
+
+  // Methods for communicating message receipt and error status to client code.
+  std::unique_ptr<Delegate> delegate_;
+
+  // Write flow state machine state.
+  WriteState write_state_;
+
+  // Read flow state machine state.
+  ReadState read_state_;
+
+  // The last error encountered by the channel.
+  ChannelError error_state_;
+
+  // Connection metadata for logging purposes.
+  // Socket ID assigned by ApiResourceManager.
+  int channel_id_;
+
+  // IP address of the remote end.
+  const net::IPEndPoint ip_endpoint_;
+
+  // Authentication level for the connection.
+  ChannelAuthType channel_auth_;
+
+  // Accumulates details of events and errors, for debugging purposes.
+  scoped_refptr<Logger> logger_;
+
+  SEQUENCE_CHECKER(sequence_checker_);
+
+  DISALLOW_COPY_AND_ASSIGN(CastTransportImpl);
+};
+}  // namespace cast_channel
+}  // namespace api
+}  // namespace extensions
+
+#endif  // EXTENSIONS_BROWSER_API_CAST_CHANNEL_CAST_TRANSPORT_H_