refactor(ivy): generate vars in component defs (#25562)

PR Close #25562

packages/core/src/render3/interfaces/definition.ts

@@ -210,6 +210,14 @@ export interface ComponentDef<T, Selector extends string> extends DirectiveDef<T
   // TODO(kara): remove queries from this count
   consts: number;
 
+  /**
+   * The number of bindings in this component template (including pure fn bindings).
+   *
+   * Used to calculate the length of the component's LViewData array, so we
+   * can pre-fill the array and set the host binding start index.
+   */
+  vars: number;
+
   /**
    * Query-related instructions for a component.
    */