[cast_channel] Make CastMessageHandler a CastSocket::Observer instead of CastTransport::Delegate

components/cast_channel/cast_socket.cc

Index: components/cast_channel/cast_socket.cc
diff --git a/components/cast_channel/cast_socket.cc b/components/cast_channel/cast_socket.cc
index e60004ed228f1e5c1a2f6ce9ebd0e2150cc12fbe..e87c392565a666350d4f83803569f460f78d5041 100644
--- a/components/cast_channel/cast_socket.cc
+++ b/components/cast_channel/cast_socket.cc
@@ -240,14 +240,13 @@ void CastSocketImpl::SetTransportForTesting(
   transport_ = std::move(transport);
 }
 
-void CastSocketImpl::Connect(std::unique_ptr<CastTransport::Delegate> delegate,
-                             base::Callback<void(ChannelError)> callback) {
+void CastSocketImpl::Connect(base::Callback<void(ChannelError)> callback) {
   DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
   VLOG_WITH_CONNECTION(1) << "Connect readyState = "
                           << ::cast_channel::ReadyStateToString(ready_state_);
   DCHECK_EQ(ConnectionState::START_CONNECT, connect_state_);
 
-  delegate_ = std::move(delegate);
+  delegate_ = base::MakeUnique<CastSocketMessageDelegate>(this);
 
   if (ready_state_ != ReadyState::NONE) {
     callback.Run(ChannelError::CONNECT_ERROR);
@@ -274,6 +273,12 @@ CastTransport* CastSocketImpl::transport() const {
   return transport_.get();
 }
 
+void CastSocketImpl::AddObserver(Observer* observer) {
+  DCHECK(observer);
+  if (!observers_.HasObserver(observer))
+    observers_.AddObserver(observer);
+}
+
 void CastSocketImpl::OnConnectTimeout() {
   DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
   // Stop all pending connection setup tasks and report back to the client.
@@ -603,5 +608,28 @@ void CastSocketImpl::SetErrorState(ChannelError error_state) {
   delegate_->OnError(error_state_);
 }
 
+CastSocketImpl::CastSocketMessageDelegate::CastSocketMessageDelegate(
+    cast_channel::CastSocketImpl* socket)
+    : socket_(socket) {
+  DCHECK(socket_);
+}
+
+CastSocketImpl::CastSocketMessageDelegate::~CastSocketMessageDelegate() {}
+
+// CastTransport::Delegate implementation.
+void CastSocketImpl::CastSocketMessageDelegate::OnError(
+    cast_channel::ChannelError error_state) {
+  for (auto& observer : socket_->observers_)
+    observer.OnError(*socket_, error_state);
+}
+
+void CastSocketImpl::CastSocketMessageDelegate::OnMessage(
+    const cast_channel::CastMessage& message) {
+  for (auto& observer : socket_->observers_)
+    observer.OnMessage(*socket_, message);
+}
+
+void CastSocketImpl::CastSocketMessageDelegate::Start() {}
+
 }  // namespace cast_channel
 #undef VLOG_WITH_CONNECTION