don't hardcode "mSurface" throughout our source code

this is used in a few places to get access to the android.view.Surface
native surface. use a macro instead. Also rename the field to mNativeSurface.

Change-Id: I1c6dea14abd6b8b1392c7f97b304115999355094
diff --git a/media/libmedia/IOMX.cpp b/media/libmedia/IOMX.cpp
index 01b6737..f3804b8 100644
--- a/media/libmedia/IOMX.cpp
+++ b/media/libmedia/IOMX.cpp
@@ -57,7 +57,7 @@
         return NULL;
     }
 
-    jfieldID surfaceID = env->GetFieldID(surfaceClass, "mSurface", "I");
+    jfieldID surfaceID = env->GetFieldID(surfaceClass, ANDROID_VIEW_SURFACE_JNI_ID, "I");
     if (surfaceID == NULL) {
         LOGE("Can't find Surface.mSurface");
         return NULL;