[Presentation API] Add layout test for connection.close() and fix test failures

third_party/WebKit/public/platform/modules/presentation/WebPresentationConnection.h

 // Copyright 2017 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 WebPresentationConnection_h
 #define WebPresentationConnection_h
 
 #include "public/platform/WebCommon.h"
 
 #include <memory>
@@ skipping 12 matching lines @@
   // Takes ownership of |proxy| and stores it in connection object. Should be
   // called only once.
   virtual void bindProxy(std::unique_ptr<WebPresentationConnectionProxy>) = 0;
 
   // Notifies the presentation about new message.
   virtual void didReceiveTextMessage(const WebString& message) = 0;
   virtual void didReceiveBinaryMessage(const uint8_t* data, size_t length) = 0;
 
   // Notifies the connection about its state change.
   virtual void didChangeState(WebPresentationConnectionState) = 0;
+
+  // Notifies the connection about its state change to 'closed' with "Closed"
+  // reason.
+  virtual void didClose() = 0;
 };
 
 }  // namespace blink
 
 #endif  // WebPresentationConnection_h