hwc2: create and destroy layers

Client can create and destroy layers

Test: Add "TARGET_USES_HWC2 := true" to BoardConfig.mk.
      Recompile.
      Run testcases: https://android-review.googlesource.com/#/q/project:
            platform/frameworks/native+branch:master+topic:test-hwc2

Change-Id: I3ff3f1eee28055382cebfb3199da5017cc55f53d
6 files changed