Adding single-direction scroll options to inject options (#4651)

* Adding single directions scroll config to inject options

core/inject.js

@@ -379,9 +379,14 @@ Blockly.init_ = function(mainWorkspace) {
   }
 
   if (options.moveOptions && options.moveOptions.scrollbars) {
+    var horizontalScroll = options.moveOptions.scrollbars === true ||
+        !!options.moveOptions.scrollbars.horizontal;
+    var verticalScroll = options.moveOptions.scrollbars === true ||
+        !!options.moveOptions.scrollbars.vertical;
     mainWorkspace.scrollbar =
         new Blockly.ScrollbarPair(
-            mainWorkspace, true, true, 'blocklyMainWorkspaceScrollbar');
+            mainWorkspace, horizontalScroll, verticalScroll,
+            'blocklyMainWorkspaceScrollbar');
     mainWorkspace.scrollbar.resize();
   } else {
     mainWorkspace.setMetrics({x: 0.5, y: 0.5});

core/options.js

@@ -134,7 +134,7 @@ Blockly.Options = function(options) {
   /** @type {!Blockly.Options.MoveOptions} */
   this.moveOptions = Blockly.Options.parseMoveOptions_(options, hasCategories);
   /** @deprecated  January 2019 */
-  this.hasScrollbars = this.moveOptions.scrollbars;
+  this.hasScrollbars = !!this.moveOptions.scrollbars;
   /** @type {boolean} */
   this.hasTrashcan = hasTrashcan;
   /** @type {number} */
@@ -205,12 +205,21 @@ Blockly.Options.GridOptions;
  * Move Options.
  * @typedef {{
  *     drag: boolean,
- *     scrollbars: boolean,
+ *     scrollbars: (boolean | !Blockly.Options.ScrollbarOptions),
  *     wheel: boolean
  * }}
  */
 Blockly.Options.MoveOptions;
 
+/**
+ * Scrollbar Options.
+ * @typedef {{
+ *     horizontal: boolean,
+ *     vertical: boolean
+ * }}
+ */
+Blockly.Options.ScrollbarOptions;
+
 /**
  * Zoom Options.
  * @typedef {{
@@ -252,9 +261,23 @@ Blockly.Options.parseMoveOptions_ = function(options, hasCategories) {
   var moveOptions = {};
   if (move['scrollbars'] === undefined && options['scrollbars'] === undefined) {
     moveOptions.scrollbars = hasCategories;
+  } else if (typeof move['scrollbars'] == 'object') {
+    moveOptions.scrollbars = {};
+    moveOptions.scrollbars.horizontal = !!move['scrollbars']['horizontal'];
+    moveOptions.scrollbars.vertical = !!move['scrollbars']['vertical'];
+    // Convert scrollbars object to boolean if they have the same value.
+    // This allows us to easily check for whether any scrollbars exist using
+    // !!moveOptions.scrollbars.
+    if (moveOptions.scrollbars.horizontal && moveOptions.scrollbars.vertical) {
+      moveOptions.scrollbars = true;
+    } else if (!moveOptions.scrollbars.horizontal &&
+        !moveOptions.scrollbars.vertical) {
+      moveOptions.scrollbars = false;
+    }
   } else {
     moveOptions.scrollbars = !!move['scrollbars'] || !!options['scrollbars'];
   }
+
   if (!moveOptions.scrollbars || move['wheel'] === undefined) {
     // Defaults to false so that developers' settings don't appear to change.
     moveOptions.wheel = false;

core/workspace_svg.js

@@ -1659,7 +1659,7 @@ Blockly.WorkspaceSvg.prototype.isDraggable = function() {
  * @return {boolean} True if the workspace is movable, false otherwise.
  */
 Blockly.WorkspaceSvg.prototype.isMovable = function() {
-  return (this.options.moveOptions && this.options.moveOptions.scrollbars) ||
+  return (this.options.moveOptions && !!this.options.moveOptions.scrollbars) ||
       (this.options.moveOptions && this.options.moveOptions.wheel) ||
       (this.options.moveOptions && this.options.moveOptions.drag) ||
       (this.options.zoomOptions && this.options.zoomOptions.wheel) ||