Update the how we propogate parent type and appId

SurfaceFlinger sends each layer's metadata (i.e. type and appId) to
the hardware composer. The feature was introduced in Android Q for
the 2D-in-VR feature that Daydream uses. The logic was introduced in
ag/3738015.

When sending layer information to hal, layers also inherit type and
app id from parent node when parent node has valid type/appId.

However, there are some descendents about what is the invalid type and
appId. The original CL ag/3738015 assumes -1 is invalid, while newer
CLs ag/6072974 and unittests assumes 0 as default value.

Actually, the current unittests is correct, for two reasons:

1/ window type comes from WindowManager.LayoutParams and all values
   defined here are non-zero.
2/ appId is basically app's UID, which should not be zero (i.e. app
   never runs under root).

Thus, I now have enough reason to conclude that the parent type and
appId should be tested with "type > 0 && appId > 0". In another word,
the parent is only valid when the type and appId are both non-zero.

Bug: 133452166
Test: Inspect the output of
      "adb shell lshal debug
      android.hardware.graphics.composer@2.1::IComposer/vr"
      and verify that each layer's type and app_id are correctly
      populated.
Test: atest libsurfaceflinger_unittest

Change-Id: Ib039a54bba241839f49e0be6d87c021001b470e9