[CrOS Multidevice] Remove secure_channel::ClientChannel::Disconnect() method.

This method is unnecessary; if clients wish to disconnect a ClientChannel,
they simply need to delete the object.

Bug: 824568, 752273
Change-Id: I5ba7268743f8aabb208bc4add9ed849a982c7465
Reviewed-on: https://chromium-review.googlesource.com/1105609Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Ryan Hansberry <hansberry@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568340}

chromeos/services/secure_channel/public/cpp/client/client_channel.cc

@@ -35,12 +35,6 @@ bool ClientChannel::SendMessage(const std::string& payload,
   return true;
 }
 
-void ClientChannel::Disconnect() {
-  // Clients should not attempt to disconnect an already-disconnected channel.
-  DCHECK(!is_disconnected_);
-  PerformDisconnection();
-}
-
 void ClientChannel::AddObserver(Observer* observer) {
   observer_list_.AddObserver(observer);
 }

chromeos/services/secure_channel/public/cpp/client/client_channel.h

@@ -19,6 +19,9 @@ namespace secure_channel {
 // A full-duplex communication channel which is guaranteed to be authenticated
 // (i.e., the two sides of the channel both belong to the same underlying user).
 // All messages sent and received over the channel are encrypted.
+//
+// If clients wish to disconnect the channel, they simply need to delete the
+// object.
 class ClientChannel {
  public:
   class Observer {
@@ -40,11 +43,6 @@ class ClientChannel {
   bool SendMessage(const std::string& payload,
                    base::OnceClosure on_sent_callback);
 
-  // Disconnects this channel. Note that disconnection is an asynchronous
-  // operation; observers will be notified when disconnection completes via the
-  // OnDisconnected() callback.
-  void Disconnect();
-
   bool is_disconnected() const { return is_disconnected_; }
 
   void AddObserver(Observer* observer);
@@ -62,11 +60,6 @@ class ClientChannel {
   virtual void PerformGetConnectionMetadata(
       base::OnceCallback<void(mojom::ConnectionMetadata)> callback) = 0;
 
-  // Performs the actual logic of disconnecting. By the time this function is
-  // called, it has already been confirmed that the channel is still indeed
-  // connected.
-  virtual void PerformDisconnection() = 0;
-
   void NotifyDisconnected();
   void NotifyMessageReceived(const std::string& payload);
 

chromeos/services/secure_channel/public/cpp/client/client_channel_impl.cc

@@ -72,12 +72,6 @@ void ClientChannelImpl::PerformSendMessage(const std::string& payload,
   channel_->SendMessage(payload, std::move(on_sent_callback));
 }
 
-void ClientChannelImpl::PerformDisconnection() {
-  channel_.reset();
-  binding_.Close();
-  NotifyDisconnected();
-}
-
 void ClientChannelImpl::OnChannelDisconnected(
     uint32_t disconnection_reason,
     const std::string& disconnection_description) {
@@ -86,7 +80,9 @@ void ClientChannelImpl::OnChannelDisconnected(
                << disconnection_description;
   }
 
-  PerformDisconnection();
+  channel_.reset();
+  binding_.Close();
+  NotifyDisconnected();
 }
 
 void ClientChannelImpl::FlushForTesting() {

chromeos/services/secure_channel/public/cpp/client/client_channel_impl.h

@@ -44,7 +44,6 @@ class ClientChannelImpl : public ClientChannel, public mojom::MessageReceiver {
       base::OnceCallback<void(mojom::ConnectionMetadata)> callback) override;
   void PerformSendMessage(const std::string& payload,
                           base::OnceClosure on_sent_callback) override;
-  void PerformDisconnection() override;
 
   // MessageReceiver:
   void OnMessageReceived(const std::string& message) override;

chromeos/services/secure_channel/public/cpp/client/client_channel_impl_unittest.cc

@@ -166,12 +166,6 @@ TEST_F(SecureChannelClientChannelImplTest, TestReceiveMessage) {
   EXPECT_EQ("payload", fake_observer_->received_messages()[0]);
 }
 
-TEST_F(SecureChannelClientChannelImplTest, TestDisconnectByClient) {
-  client_channel_->Disconnect();
-
-  VerifyChannelDisconnected();
-}
-
 TEST_F(SecureChannelClientChannelImplTest, TestDisconnectRemotely) {
   fake_channel_->DisconnectGeneratedPtr();
 

chromeos/services/secure_channel/public/cpp/client/fake_client_channel.cc

@@ -25,10 +25,6 @@ void FakeClientChannel::PerformSendMessage(const std::string& payload,
       std::make_pair(payload, std::move(on_sent_callback)));
 }
 
-void FakeClientChannel::PerformDisconnection() {
-  NotifyDisconnected();
-}
-
 }  // namespace secure_channel
 
 }  // namespace chromeos

chromeos/services/secure_channel/public/cpp/client/fake_client_channel.h

@@ -38,7 +38,6 @@ class FakeClientChannel : public ClientChannel {
       base::OnceCallback<void(mojom::ConnectionMetadata)> callback) override;
   void PerformSendMessage(const std::string& payload,
                           base::OnceClosure on_sent_callback) override;
-  void PerformDisconnection() override;
 
   mojom::ConnectionMetadata connection_metadata_;
   std::vector<std::pair<std::string, base::OnceClosure>> sent_messages_;