First prototype atttempting to support an external display

both API and implementation will change, this is just a prototype
intended to show feasability.

SurfaceFlinger is passed an ISurfaceTexture through a new
callback, it is in turn used to create an EGLSurface which
surfaceflinger will draw into in addition to the main screen.

Change-Id: Id0bbb0b854bb7bae44d57246a90b65d4567f9a21
diff --git a/services/surfaceflinger/DisplayHardware/DisplayHardware.h b/services/surfaceflinger/DisplayHardware/DisplayHardware.h
index f029a0a..31662dd 100644
--- a/services/surfaceflinger/DisplayHardware/DisplayHardware.h
+++ b/services/surfaceflinger/DisplayHardware/DisplayHardware.h
@@ -96,6 +96,7 @@
 
     uint32_t getPageFlipCount() const;
     EGLDisplay getEGLDisplay() const { return mDisplay; }
+    EGLConfig getEGLConfig() const { return mConfig; }
 
     void dump(String8& res) const;