Add glOrtho equivalent to the OpenGL ES 2.0 renderer.

Change-Id: I063dad3d81dab7833acb1e7a9c7121f8efd2a044
diff --git a/libs/hwui/UIOpenGLRenderer.h b/libs/hwui/UIOpenGLRenderer.h
index b0fb73f..3b95e6a 100644
--- a/libs/hwui/UIOpenGLRenderer.h
+++ b/libs/hwui/UIOpenGLRenderer.h
@@ -26,6 +26,10 @@
 
     void setViewport(int width, int height);
     void prepare();
+
+private:
+    float mOrthoMatrix[16];
+
 };
 
 }; // namespace android