fix [3260137] Sometimes front-facing camera mirroring is wrong

make sure to take the buffer's orientation into account.

Change-Id: I9fef89e66368ad2dec1cb8c7b77ac2b3b4858efb
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index fe4379d..85fd2c7 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -204,7 +204,8 @@
         return;
     }
 
-    hwcl->transform = mOrientation;
+    Transform tr(Transform(mOrientation) * Transform(mBufferTransform));
+    hwcl->transform = tr.getOrientation();
 
     if (needsBlending()) {
         hwcl->blending = mPremultipliedAlpha ?