Add unit tests for planner's LayerState

Bug: 180639488
Test: libcompositionengine_test

Change-Id: I3660d58c0c8e17b5e9a6378e5c9a5ca5842f2cad
diff --git a/services/surfaceflinger/CompositionEngine/Android.bp b/services/surfaceflinger/CompositionEngine/Android.bp
index 1c47691..d297d74 100644
--- a/services/surfaceflinger/CompositionEngine/Android.bp
+++ b/services/surfaceflinger/CompositionEngine/Android.bp
@@ -105,6 +105,7 @@
     srcs: [
         "tests/planner/CachedSetTest.cpp",
         "tests/planner/FlattenerTest.cpp",
+        "tests/planner/LayerStateTest.cpp",
         "tests/CompositionEngineTest.cpp",
         "tests/DisplayColorProfileTest.cpp",
         "tests/DisplayTest.cpp",