emulator: opengl: Add support for unix sockets.

This patch allows the OpenGLES rendering library to use Unix
sockets instead of TCP ones when communicating with its clients.
On certain benchmarks (e.g. 0xBench teapot), this provides a
noticeable improvement (x1.05 fps) without any other changes.

On practice, Unix sockets are faster than TCP sockets, even
local ones. Also, this introduces a moderate amount of
abstraction that will allow us to use Win32 named pipes
on Windows (where TCP sockets are much slower than they
are on Unix).

Note that by default, TCP streams are still used.
The client (emulator) must call the new API 'setStreamMode'
to change it to STREAM_MODE_UNIX between 'initLibrary' and
'startOpenglRenderer' calls.

+ Adjust callers / user appropriately.

Change-Id: I4105bbf07541f3146b50a58d1a5b51e8cf044fab

tools/emulator/opengl/shared/OpenglCodecCommon/UnixStream.h

@@ -0,0 +1,31 @@
+/*
+* Copyright (C) 2011 The Android Open Source Project
+*
+* Licensed under the Apache License, Version 2.0 (the "License");
+* you may not use this file except in compliance with the License.
+* You may obtain a copy of the License at
+*
+* http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+#ifndef __UNIX_STREAM_H
+#define __UNIX_STREAM_H
+
+#include "SocketStream.h"
+
+class UnixStream : public SocketStream {
+public:
+    explicit UnixStream(size_t bufsize = 10000);
+    virtual int listen(unsigned short port);
+    virtual SocketStream *accept();
+    virtual int connect(unsigned short port);
+private:
+    UnixStream(int sock, size_t bufSize);
+};
+
+#endif