Enqueue mDns requests if send on socket in progress.

net/dns/mdns_client_impl.h

Index: net/dns/mdns_client_impl.h
diff --git a/net/dns/mdns_client_impl.h b/net/dns/mdns_client_impl.h
index 76607880befc42c77a6d1d7a08399eebac34efec..eda53c3af954c99331b1eeac074f4789eeafd255 100644
--- a/net/dns/mdns_client_impl.h
+++ b/net/dns/mdns_client_impl.h
@@ -52,7 +52,7 @@ class NET_EXPORT_PRIVATE MDnsConnection {
 
   // Both methods return true if at least one of the socket handlers succeeded.
   bool Init(MDnsSocketFactory* socket_factory);
-  bool Send(IOBuffer* buffer, unsigned size);
+  bool Send(const scoped_refptr<IOBufferWithSize>& buffer);
 
  private:
   class SocketHandler {
@@ -62,7 +62,7 @@ class NET_EXPORT_PRIVATE MDnsConnection {
     ~SocketHandler();
 
     int Start();
-    int Send(IOBuffer* buffer, unsigned size);
+    int Send(const scoped_refptr<IOBufferWithSize>& buffer);
 
    private:
     int DoLoop(int rv);
@@ -76,6 +76,8 @@ class NET_EXPORT_PRIVATE MDnsConnection {
     IPEndPoint recv_addr_;
     DnsResponse response_;
     IPEndPoint multicast_addr_;
+    bool send_in_progress_;
+    std::queue<scoped_refptr<IOBufferWithSize> > send_queue_;
 
     DISALLOW_COPY_AND_ASSIGN(SocketHandler);
   };