Merge "surfaceflinger: fix missing pure virtual declarations." am: f4e70632b9

Original change: https://android-review.googlesource.com/c/platform/frameworks/native/+/2392152

Change-Id: Ic0503974736aedbd8bc6e8a3794163165e1623f2
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>