Force-reset drawable paddings when popup background is updated

cascade/src/main/java/me/saket/cascade/ForcePaddingsDrawable.kt

@@ -0,0 +1,17 @@
+package me.saket.cascade
+
+import android.graphics.Rect
+import android.graphics.drawable.Drawable
+
+/**
+ * Workaround for [https://issuetracker.google.com/u/1/issues/171026918].
+ *
+ * The default popup background contains internal paddings, that aren't reset even if the
+ * background is overridden using a [CascadePopupMenu.Styler].
+ */
+internal class ForcePaddingsDrawable(delegate: Drawable) : DrawableWrapperCompat(delegate) {
+  override fun getPadding(padding: Rect): Boolean {
+    super.getPadding(padding)
+    return true
+  }
+}

cascade/src/main/java/me/saket/cascade/HeightAnimatableViewFlipper.kt

@@ -121,7 +121,15 @@ open class HeightAnimatableViewFlipper(context: Context) : ViewFlipper2(context)
 
   @Suppress("DEPRECATION")
   override fun setBackgroundDrawable(background: Drawable?) {
-    super.setBackgroundDrawable(background?.let(::HeightClipDrawable))
+    if (background == null) {
+      super.setBackgroundDrawable(null)
+    } else {
+      super.setBackgroundDrawable(
+        HeightClipDrawable(
+          ForcePaddingsDrawable(background)
+        )
+      )
+    }
   }
 
   private fun background(): HeightClipDrawable? {