Use msgId in connection

Work with the previously defined msgId in connection. This is the first
step in ensuring that all msgIds are unique at the connection scope.
Currently this doesn't fix the original problem though and we need to
work with this same msgId in the session too.

Author: ankur22

common/connection.go

@@ -125,7 +125,7 @@ type Connection struct {
 	done         chan struct{}
 	closing      chan struct{}
 	shutdownOnce sync.Once
-	msgID        int64
+	msgID        *msgID
 
 	sessionsMu sync.RWMutex
 	sessions   map[target.SessionID]*Session
@@ -163,7 +163,7 @@ func NewConnection(ctx context.Context, wsURL string, logger *log.Logger) (*Conn
 		errorCh:          make(chan error),
 		done:             make(chan struct{}),
 		closing:          make(chan struct{}),
-		msgID:            0,
+		msgID:            &msgID{},
 		sessions:         make(map[target.SessionID]*Session),
 	}
 
@@ -509,7 +509,7 @@ func (c *Connection) Close(args ...goja.Value) {
 // Execute implements cdproto.Executor and performs a synchronous send and receive.
 func (c *Connection) Execute(ctx context.Context, method string, params easyjson.Marshaler, res easyjson.Unmarshaler) error {
 	c.logger.Debugf("connection:Execute", "wsURL:%q method:%q", c.wsURL, method)
-	id := atomic.AddInt64(&c.msgID, 1)
+	id := c.msgID.new()
 
 	// Setup event handler used to block for response to message being sent.
 	ch := make(chan *cdproto.Message, 1)