Merge "Fix Keep rules for MotionLayout" into tm-qpr-dev am: 9c448ce68a

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/19483419

Change-Id: Ibdbee472f3abe8188e26bae8b0c59c91f9136b37
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

packages/SystemUI/proguard.flags

@@ -11,6 +11,11 @@
 -keep class * extends com.android.systemui.CoreStartable
 -keep class * implements com.android.systemui.CoreStartable$Injector
 
+# Needed for builds to properly initialize KeyFrames from xml scene
+-keepclassmembers class * extends androidx.constraintlayout.motion.widget.Key {
+  public <init>();
+}
+
 -keepclasseswithmembers class * {
     public <init>(android.content.Context, android.util.AttributeSet);
 }