Create new class "CastTransport", which encapsulates the message read and write event loops.

extensions/browser/api/cast_channel/cast_channel_api.cc

Index: extensions/browser/api/cast_channel/cast_channel_api.cc
diff --git a/extensions/browser/api/cast_channel/cast_channel_api.cc b/extensions/browser/api/cast_channel/cast_channel_api.cc
index ee888cb2602536cfbea8f03a134ce05f7e9d6b43..9d711a48c0c7910804a435ce46cd76f4fa3ae8c6 100644
--- a/extensions/browser/api/cast_channel/cast_channel_api.cc
+++ b/extensions/browser/api/cast_channel/cast_channel_api.cc
@@ -131,27 +131,14 @@ CastChannelAPI::GetFactoryInstance() {
   return g_factory.Pointer();
 }
 
-scoped_ptr<CastSocket> CastChannelAPI::CreateCastSocket(
-    const std::string& extension_id, const net::IPEndPoint& ip_endpoint,
-    ChannelAuthType channel_auth, const base::TimeDelta& timeout) {
-  if (socket_for_test_.get()) {
-    return socket_for_test_.Pass();
-  } else {
-    return scoped_ptr<CastSocket>(
-        new CastSocket(extension_id,
-                       ip_endpoint,
-                       channel_auth,
-                       this,
-                       ExtensionsBrowserClient::Get()->GetNetLog(),
-                       timeout,
-                       logger_));
-  }
-}
-
 void CastChannelAPI::SetSocketForTest(scoped_ptr<CastSocket> socket_for_test) {
   socket_for_test_ = socket_for_test.Pass();
 }
 
+scoped_ptr<cast_channel::CastSocket> CastChannelAPI::GetSocketForTest() {
+  return socket_for_test_.Pass();
+}
+
 void CastChannelAPI::OnError(const CastSocket* socket,
                              cast_channel::ChannelError error_state,
                              const cast_channel::LastErrors& last_errors) {
@@ -367,13 +354,19 @@ bool CastChannelOpenFunction::Prepare() {
 void CastChannelOpenFunction::AsyncWorkStart() {
   DCHECK(api_);
   DCHECK(ip_endpoint_.get());
-  scoped_ptr<CastSocket> socket = api_->CreateCastSocket(
-      extension_->id(),
-      *ip_endpoint_,
-      channel_auth_,
-      base::TimeDelta::FromMilliseconds(connect_info_->timeout.get()
-                                            ? *connect_info_->timeout
-                                            : kDefaultConnectTimeoutMillis));
+  scoped_ptr<CastSocket> socket = api_->GetSocketForTest();
+  if (!socket.get()) {
+    socket.reset(new CastSocket(
+        extension_->id(),
+        *ip_endpoint_,
+        channel_auth_,
+        api_,
+        ExtensionsBrowserClient::Get()->GetNetLog(),
+        base::TimeDelta::FromMilliseconds(connect_info_->timeout.get()
+                                              ? *connect_info_->timeout
+                                              : kDefaultConnectTimeoutMillis),
+        api_->GetLogger()));
+  }
   new_channel_id_ = AddSocket(socket.release());
   CastSocket* new_socket = GetSocket(new_channel_id_);
   api_->GetLogger()->LogNewSocketEvent(*new_socket);
@@ -424,11 +417,15 @@ bool CastChannelSendFunction::Prepare() {
 }
 
 void CastChannelSendFunction::AsyncWorkStart() {
-  CastSocket* socket = GetSocketOrCompleteWithError(
-      params_->channel.channel_id);
-  if (socket)
-    socket->SendMessage(params_->message,
-                        base::Bind(&CastChannelSendFunction::OnSend, this));
+  CastSocket* socket = GetSocket(params_->channel.channel_id);
+  if (!socket) {
+    SetResultFromError(params_->channel.channel_id,
+                       cast_channel::CHANNEL_ERROR_INVALID_CHANNEL_ID);
+    AsyncWorkCompleted();
+    return;
+  }
+  socket->SendMessage(params_->message,
+                      base::Bind(&CastChannelSendFunction::OnSend, this));
 }
 
 void CastChannelSendFunction::OnSend(int result) {
@@ -455,10 +452,14 @@ bool CastChannelCloseFunction::Prepare() {
 }
 
 void CastChannelCloseFunction::AsyncWorkStart() {
-  CastSocket* socket = GetSocketOrCompleteWithError(
-      params_->channel.channel_id);
-  if (socket)
+  CastSocket* socket = GetSocket(params_->channel.channel_id);
+  if (!socket) {
+    SetResultFromError(params_->channel.channel_id,
+                       cast_channel::CHANNEL_ERROR_INVALID_CHANNEL_ID);
+    AsyncWorkCompleted();
+  } else {
     socket->Close(base::Bind(&CastChannelCloseFunction::OnClose, this));
+  }
 }
 
 void CastChannelCloseFunction::OnClose(int result) {