Let layoutShallowEquals compare any layout-shaped object

src/state/layout-types.ts

@@ -150,10 +150,11 @@ export type Layout =
   | PipLayout;
 
 /**
- * Tests whether the top-level properties and array elements of layout `a` are
+ * Tests whether the top-level properties and array elements of `a` are equal
- * equal to those of layout `b`. Useful for deduping redundant layout updates.
+ * to those of `b`. Useful for deduping redundant layout and layout media
+ * updates.
  */
-export function layoutShallowEquals(a: Layout, b: Layout): boolean {
+export function layoutShallowEquals<T extends object>(a: T, b: T): boolean {
   // If a and b have the same number of keys and every key in a is also in b,
   // then they have the same keys.
   const aKeys = Object.keys(a);