Bounding Box interface (#3906)

* Add an interface describing a bounding box registered on the workspace

* Clear the bounding box array

* PR comments

* Update chromedriver

core/interfaces/i_bounding_box.js

@@ -0,0 +1,31 @@
+/**
+ * @license
+ * Copyright 2020 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+/**
+ * @fileoverview The interface for a bounding box.
+ * @author samelh@google.com (Sam El-Husseini)
+ */
+
+'use strict';
+
+goog.provide('Blockly.IBoundingBox');
+
+goog.requireType('Blockly.utils.Rect');
+
+
+/**
+ * A bounding box interface.
+ * @interface
+ */
+Blockly.IBoundingBox = function() {};
+
+/**
+ * Returns the coordinates of a bounding box describing the dimensions of this
+ * element.
+ * Coordinate system: workspace coordinates.
+ * @return {!Blockly.utils.Rect} Object with coordinates of the bounding box.
+ */
+Blockly.IBoundingBox.prototype.getBoundingRectangle;