NETWORKING: Enter Session

Session allows to reuse SessionRequests to the same host by making them
keeping alive connection. Turns out, though, that libcurl already does
that for us, and we didn't gain any speedup we thought we'd get.

Usage:
```
Networking::Session s;
Networking::SessionRequest *request = s.get(url);
request->startAndWait();
warning("HTTP GET: %s", request->text());
s.close();
```

You can still use SessionRequest without Session (but you can't put them
on stack!):
```
Networking::SessionRequest *request = new
Networking::SessionRequest(url);
request->startAndWait();
warning("HTTP GET: %s", request->text());
request->close();
```

1 files changed, 45 insertions, 0 deletions

diff --git a/backends/networking/curl/session.h b/backends/networking/curl/session.h
new file mode 100644
index 0000000000..d3aa5807a7
--- /dev/null
+++ b/backends/networking/curl/session.h
@@ -0,0 +1,45 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef BACKENDS_NETWORKING_CURL_SESSION_H
+#define BACKENDS_NETWORKING_CURL_SESSION_H
+
+#include "backends/networking/curl/sessionrequest.h"
+
+namespace Networking {
+
+class Session {
+protected:
+	Common::String _prefix;
+	SessionRequest *_request;
+
+public:
+	Session(Common::String prefix = "");
+	~Session();
+
+	SessionRequest *get(Common::String url, DataCallback cb = nullptr, ErrorCallback ecb = nullptr);
+	void close();
+};
+
+} // End of namespace Networking
+
+#endif