[cast_channel] Make cast_channel related files not depend on "cast_channel.h"

extensions/browser/api/cast_channel/keep_alive_delegate.cc

 // 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.
 
 #include "extensions/browser/api/cast_channel/keep_alive_delegate.h"
 
 #include <string>
 #include <utility>
 
 #include "base/json/json_reader.h"
@@ skipping 30 matching lines @@
 }
 
 }  // namespace
 
 // static
 const char KeepAliveDelegate::kHeartbeatPingType[] = "PING";
 
 // static
 const char KeepAliveDelegate::kHeartbeatPongType[] = "PONG";
 
+using ::cast_channel::ChannelError;
+
 // static
 CastMessage KeepAliveDelegate::CreateKeepAliveMessage(
     const char* message_type) {
   CastMessage output;
   output.set_protocol_version(CastMessage::CASTV2_1_0);
   output.set_source_id(kPingSenderId);
   output.set_destination_id(kPingReceiverId);
   output.set_namespace_(kHeartbeatNamespace);
   base::DictionaryValue type_dict;
   type_dict.SetString(kTypeNodeId, message_type);
@@ skipping 78 matching lines @@
                           base::Unretained(this), message_type));
 }
 
 void KeepAliveDelegate::SendKeepAliveMessageComplete(const char* message_type,
                                                      int rv) {
   VLOG(2) << "Sending " << message_type << " complete, rv=" << rv;
   if (rv != net::OK) {
     // An error occurred while sending the ping response.
     VLOG(1) << "Error sending " << message_type;
     logger_->LogSocketEventWithRv(socket_->id(), proto::PING_WRITE_ERROR, rv);
-    OnError(cast_channel::CHANNEL_ERROR_SOCKET_ERROR);
+    OnError(ChannelError::CAST_SOCKET_ERROR);
   }
 }
 
 void KeepAliveDelegate::LivenessTimeout() {
-  OnError(cast_channel::CHANNEL_ERROR_PING_TIMEOUT);
+  OnError(ChannelError::PING_TIMEOUT);
   Stop();
 }
 
 // CastTransport::Delegate interface.
 void KeepAliveDelegate::OnError(ChannelError error_state) {
   DCHECK(thread_checker_.CalledOnValidThread());
-  VLOG(1) << "KeepAlive::OnError: " << error_state;
+  VLOG(1) << "KeepAlive::OnError: "
+          << ::cast_channel::ChannelErrorToString(error_state);
   inner_delegate_->OnError(error_state);
   Stop();
 }
 
 void KeepAliveDelegate::OnMessage(const CastMessage& message) {
   DCHECK(thread_checker_.CalledOnValidThread());
   VLOG(2) << "KeepAlive::OnMessage : " << message.payload_utf8();
 
   if (started_)
     ResetTimers();
@@ skipping 16 matching lines @@
   if (started_) {
     started_ = false;
     ping_timer_->Stop();
     liveness_timer_->Stop();
   }
 }
 
 }  // namespace cast_channel
 }  // namespace api
 }  // namespace extensions