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

extensions/browser/api/cast_channel/cast_channel_api.h

 // 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_CHANNEL_API_H_
 #define EXTENSIONS_BROWSER_API_CAST_CHANNEL_CAST_CHANNEL_API_H_
 
 #include <memory>
 #include <string>
 
@@ skipping 116 matching lines @@
   void AsyncWorkStart() override;
 
  private:
   DECLARE_EXTENSION_FUNCTION("cast.channel.open", CAST_CHANNEL_OPEN)
 
   // Defines a callback used to send events to the extension's
   // EventRouter.
   //     Parameter #0 is a scoped pointer to the event payload.
   using EventDispatchCallback = base::Callback<void(std::unique_ptr<Event>)>;
 
-  // Receives incoming messages and errors and provides additional API and
-  // origin socket context.
-  class CastMessageHandler : public cast_channel::CastTransport::Delegate {
+  // Receives incoming messages and errors and provides additional API context.
+  class CastMessageHandler : public cast_channel::CastSocket::Observer {
    public:
     CastMessageHandler(const EventDispatchCallback& ui_dispatch_cb,
-                       cast_channel::CastSocket* socket,
                        scoped_refptr<cast_channel::Logger> logger);
     ~CastMessageHandler() override;
 
-    // CastTransport::Delegate implementation.
-    void OnError(cast_channel::ChannelError error_state) override;
-    void OnMessage(const cast_channel::CastMessage& message) override;
-    void Start() override;
+    // CastSocket::Observer implementation.
+    void OnError(const cast_channel::CastSocket& socket,
+                 cast_channel::ChannelError error_state) override;
+    void OnMessage(const cast_channel::CastSocket& socket,
+                   const cast_channel::CastMessage& message) override;
 
    private:
     // Callback for sending events to the extension.
     // Should be bound to a weak pointer, to prevent any use-after-free
     // conditions.
     EventDispatchCallback const ui_dispatch_cb_;
-    cast_channel::CastSocket* const socket_;
     // Logger object for reporting error details.
     scoped_refptr<cast_channel::Logger> logger_;
 
     DISALLOW_COPY_AND_ASSIGN(CastMessageHandler);
   };
 
   // Validates that |connect_info| represents a valid IP end point and returns a
   // new IPEndPoint if so.  Otherwise returns nullptr.
   static net::IPEndPoint* ParseConnectInfo(
       const api::cast_channel::ConnectInfo& connect_info);
@@ skipping 52 matching lines @@
 
   std::unique_ptr<api::cast_channel::Close::Params> params_;
   CastChannelAPI* api_;
 
   DISALLOW_COPY_AND_ASSIGN(CastChannelCloseFunction);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_API_CAST_CHANNEL_CAST_CHANNEL_API_H_