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/system/OpenglSystemCommon/HostConnection.cpp

@@ -60,22 +60,6 @@ HostConnection *HostConnection::get()
             return NULL;
         }
 
-#if 0
-            TcpStream *stream = new TcpStream(STREAM_BUFFER_SIZE);
-            if (stream) {
-                if (stream->connect("10.0.2.2", STREAM_PORT_NUM) < 0) {
-                    LOGE("Failed to connect to host (TcpStream)!!!\n");
-                    delete stream;
-                    stream = NULL;
-                }
-                else {
-                    con->m_stream = stream;
-                    LOGE("Established TCP connection with HOST\n");
-                }
-            }
-            if (!stream)
-#endif
-
         if (useQemuPipe) {
             QemuPipeStream *stream = new QemuPipeStream(STREAM_BUFFER_SIZE);
             if (!stream) {
@@ -108,11 +92,11 @@ HostConnection *HostConnection::get()
         }
 
         // send zero 'clientFlags' to the host.
-        unsigned int *pClientFlags = 
+        unsigned int *pClientFlags =
                 (unsigned int *)con->m_stream->allocBuffer(sizeof(unsigned int));
         *pClientFlags = 0;
         con->m_stream->commitBuffer(sizeof(unsigned int));
-        
+
         LOGD("HostConnection::get() New Host Connection established %p, tid %d\n", con, gettid());
         tinfo->hostConn = con;
     }