Add the xrender backend to the window manager.

compositor/real_compositor.cc

Index: compositor/real_compositor.cc
diff --git a/compositor/real_compositor.cc b/compositor/real_compositor.cc
index a7bdf79c6b8dfc1b81e1ec92e636ba15b88f66bc..314e588d101d123b0fe795e66c43a36e29ca37b2 100644
--- a/compositor/real_compositor.cc
+++ b/compositor/real_compositor.cc
@@ -17,6 +17,8 @@
 #include "window_manager/compositor/gl/opengl_visitor.h"
 #elif defined(COMPOSITOR_OPENGLES)
 #include "window_manager/compositor/gles/opengles_visitor.h"
+#elif defined(COMPOSITOR_XRENDER)
+#include "window_manager/compositor/xrender/xrender_visitor.h"
 #endif
 #include "window_manager/compositor/layer_visitor.h"
 #include "window_manager/event_loop.h"
@@ -704,11 +706,11 @@ bool RealCompositor::StageActor::using_passthrough_projection() const {
 
 
 RealCompositor::RealCompositor(EventLoop* event_loop,
-                               XConnection* xconn,
+                               XConnection* xconn
 #if defined(COMPOSITOR_OPENGL)
-                               GLInterface* gl_interface
+                               ,GLInterface* gl_interface
 #elif defined(COMPOSITOR_OPENGLES)
-                               Gles2Interface* gl_interface
+                               ,Gles2Interface* gl_interface
 #endif
                               )
     : event_loop_(event_loop),
@@ -743,6 +745,8 @@ RealCompositor::RealCompositor(EventLoop* event_loop,
       new OpenGlDrawVisitor(gl_interface, this, default_stage_.get())
 #elif defined(COMPOSITOR_OPENGLES)
       new OpenGlesDrawVisitor(gl_interface, this, default_stage_.get())
+#elif defined(COMPOSITOR_XRENDER)
+      new XRenderDrawVisitor(this, default_stage_.get())
 #endif
       );