[chromedriver] Implement reconnection to DevTools.

chrome/test/chromedriver/net/sync_websocket.h

 // Copyright (c) 2012 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 CHROME_TEST_CHROMEDRIVER_NET_SYNC_WEBSOCKET_H_
 #define CHROME_TEST_CHROMEDRIVER_NET_SYNC_WEBSOCKET_H_
 
 #include <string>
 
 class GURL;
 
 // Proxy for using a WebSocket running on a background thread synchronously.
 class SyncWebSocket {
  public:
   virtual ~SyncWebSocket() {}
 
+  // Return true if connected, otherwise return false.
+  virtual bool IsConnected() = 0;
+
   // Connects to the WebSocket server. Returns true on success.
   virtual bool Connect(const GURL& url) = 0;
 
   // Sends message. Returns true on success.
   virtual bool Send(const std::string& message) = 0;
 
   // Receives next message. Blocks until at least one message is received or
   // the socket is closed. Returns true on success and modifies |message|.
   virtual bool ReceiveNextMessage(std::string* message) = 0;
 
   // Returns whether there are any messages that have been received and not yet
   // handled by ReceiveNextMessage.
   virtual bool HasNextMessage() = 0;
 };
 
 #endif  // CHROME_TEST_CHROMEDRIVER_NET_SYNC_WEBSOCKET_H_