make sure screenshot are in a format supported by Bitmap.java

Change-Id: I0fb9cc4088f9c1fd27e6c017b0a7c5617adb4660
diff --git a/services/surfaceflinger/SurfaceFlinger.h b/services/surfaceflinger/SurfaceFlinger.h
index ef88437..1017560 100644
--- a/services/surfaceflinger/SurfaceFlinger.h
+++ b/services/surfaceflinger/SurfaceFlinger.h
@@ -419,6 +419,7 @@
     EGLContext mEGLContext;
     EGLConfig mEGLConfig;
     EGLDisplay mEGLDisplay;
+    EGLint mEGLNativeVisualId;
     sp<IBinder> mBuiltinDisplays[DisplayDevice::NUM_DISPLAY_TYPES];
 
     // Can only accessed from the main thread, these members