Layers: Scoring Algorithm (#12958)

* Add comments for future todos

* Ensure size/position is always re-measured

* scoring

* Fix fixed-position undeclare layer

* Ensure a remeasure happens

* Fix cache and score

* Fix width/height calc

* Add force remeasurement

More information is necessary from the caller to determine whether it
should be forced.

* Lint

* Review comments

* Review comments

* Fix renames

src/log.js

@@ -379,6 +379,21 @@ export class Log {
     return /** @type {number} */ (shouldBeNumber);
   }
 
+  /**
+   * Throws an error if the first argument isn't a boolean.
+   *
+   * For more details see `assert`.
+   *
+   * @param {*} shouldBeBoolean
+   * @param {string=} opt_message The assertion message
+   * @return {boolean} The boolean value.
+   */
+  assertBoolean(shouldBeBoolean, opt_message) {
+    this.assert(!!shouldBeBoolean === shouldBeBoolean,
+        (opt_message || 'Boolean expected') + ': %s', shouldBeBoolean);
+    return /** @type {boolean} */ (shouldBeBoolean);
+  }
+
   /**
    * Asserts and returns the enum value. If the enum doesn't contain such a value,
    * the error is thrown.