Depend settings on slices in the support library

Test: make
Bug: 67996923
Change-Id: Ifcb544424df27f3faa8872e6266de286cc706d59
diff --git a/proguard.flags b/proguard.flags
index 7a403a4..0a299ed 100644
--- a/proguard.flags
+++ b/proguard.flags
@@ -27,6 +27,9 @@
 -keepclasseswithmembers class * {
     public <init>(android.content.Context, android.util.AttributeSet, int);
 }
+-keepclasseswithmembers class * {
+    public <init>(android.content.Context, android.util.AttributeSet, int, int);
+}
 
 # Keep annotated classes or class members.
 -keep @android.support.annotation.Keep class *