From ab8a11784da0eaf968fa36fbba389884cebe614c Mon Sep 17 00:00:00 2001
From: Sam El-Husseini <sam.elhusseini@gmail.com>
Date: Thu, 25 Feb 2021 17:28:11 -0500
Subject: [PATCH] Fix event related missing requires (#4656)

* Fix event related missing requires
---
 core/block.js                       | 16 +++++++++-------
 core/block_dragger.js               | 11 ++++++-----
 core/block_svg.js                   |  9 ++++++---
 core/blockly.js                     |  3 +++
 core/bubble_dragger.js              |  2 +-
 core/comment.js                     | 10 ++++++----
 core/connection.js                  |  4 ++--
 core/contextmenu.js                 |  3 ++-
 core/contextmenu_items.js           |  1 +
 core/events/block_events.js         |  5 ++---
 core/events/events.js               | 13 +++++++++++--
 core/events/ws_comment_events.js    |  3 +--
 core/field.js                       |  2 +-
 core/field_dropdown.js              |  1 -
 core/field_textinput.js             |  2 +-
 core/flyout_base.js                 |  7 +++++--
 core/gesture.js                     |  6 +++---
 core/inject.js                      |  1 +
 core/keyboard_nav/basic_cursor.js   |  1 +
 core/keyboard_nav/cursor.js         |  1 +
 core/metrics_manager.js             |  1 +
 core/mutator.js                     |  6 +++---
 core/procedures.js                  |  2 +-
 core/renderers/common/marker_svg.js |  3 ++-
 core/scrollbar.js                   |  1 +
 core/toolbox/toolbox.js             |  2 +-
 core/trashcan.js                    |  5 +++--
 core/utils/toolbox.js               |  1 +
 core/variable_map.js                |  9 ++++++---
 core/variable_model.js              |  3 ++-
 core/warning.js                     |  4 ++--
 core/workspace.js                   |  1 +
 core/workspace_comment.js           | 12 +++++++-----
 core/workspace_comment_svg.js       | 11 +++++++----
 core/workspace_svg.js               |  9 ++++++---
 core/xml.js                         | 12 ++++++------
 core/zoom_controls.js               |  4 +++-
 37 files changed, 116 insertions(+), 71 deletions(-)

diff --git a/core/block.js b/core/block.js
index a00cc911d..65f4664d9 100644
--- a/core/block.js
+++ b/core/block.js
@@ -226,7 +226,8 @@ Blockly.Block = function(workspace, prototypeName, opt_id) {
 
     // Fire a create event.
     if (Blockly.Events.isEnabled()) {
-      Blockly.Events.fire(new Blockly.Events.BlockCreate(this));
+      Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.BLOCK_CREATE))(
+          this));
     }
 
   } finally {
@@ -365,7 +366,8 @@ Blockly.Block.prototype.dispose = function(healStack) {
 
   this.unplug(healStack);
   if (Blockly.Events.isEnabled()) {
-    Blockly.Events.fire(new Blockly.Events.BlockDelete(this));
+    Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.BLOCK_DELETE))(
+        this));
   }
   Blockly.Events.disable();
 
@@ -1217,7 +1219,7 @@ Blockly.Block.prototype.setOutput = function(newBoolean, opt_check) {
  */
 Blockly.Block.prototype.setInputsInline = function(newBoolean) {
   if (this.inputsInline != newBoolean) {
-    Blockly.Events.fire(new Blockly.Events.BlockChange(
+    Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.BLOCK_CHANGE))(
         this, 'inline', null, this.inputsInline, newBoolean));
     this.inputsInline = newBoolean;
   }
@@ -1280,7 +1282,7 @@ Blockly.Block.prototype.isEnabled = function() {
  */
 Blockly.Block.prototype.setEnabled = function(enabled) {
   if (this.isEnabled() != enabled) {
-    Blockly.Events.fire(new Blockly.Events.BlockChange(
+    Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.BLOCK_CHANGE))(
         this, 'disabled', null, this.disabled, !enabled));
     this.disabled = !enabled;
   }
@@ -1317,7 +1319,7 @@ Blockly.Block.prototype.isCollapsed = function() {
  */
 Blockly.Block.prototype.setCollapsed = function(collapsed) {
   if (this.collapsed_ != collapsed) {
-    Blockly.Events.fire(new Blockly.Events.BlockChange(
+    Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.BLOCK_CHANGE))(
         this, 'collapsed', null, this.collapsed_, collapsed));
     this.collapsed_ = collapsed;
   }
@@ -1984,7 +1986,7 @@ Blockly.Block.prototype.setCommentText = function(text) {
   if (this.commentModel.text == text) {
     return;
   }
-  Blockly.Events.fire(new Blockly.Events.BlockChange(
+  Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.BLOCK_CHANGE))(
       this, 'comment', null, this.commentModel.text, text));
   this.commentModel.text = text;
   this.comment = text;  // For backwards compatibility.
@@ -2027,7 +2029,7 @@ Blockly.Block.prototype.moveBy = function(dx, dy) {
   if (this.parentBlock_) {
     throw Error('Block has parent.');
   }
-  var event = new Blockly.Events.BlockMove(this);
+  var event = new (Blockly.Events.get(Blockly.Events.BLOCK_MOVE))(this);
   this.xy_.translate(dx, dy);
   event.recordNew();
   Blockly.Events.fire(event);
diff --git a/core/block_dragger.js b/core/block_dragger.js
index 1b110e955..d7a539d4d 100644
--- a/core/block_dragger.js
+++ b/core/block_dragger.js
@@ -187,8 +187,8 @@ Blockly.BlockDragger.prototype.startBlockDrag = function(currentDragDeltaXY,
  * @private
  */
 Blockly.BlockDragger.prototype.fireDragStartEvent_ = function() {
-  var event = new Blockly.Events.BlockDrag(this.draggingBlock_, true,
-      this.draggingBlock_.getDescendants(false));
+  var event = new (Blockly.Events.get(Blockly.Events.BLOCK_DRAG))(
+      this.draggingBlock_, true, this.draggingBlock_.getDescendants(false));
   Blockly.Events.fire(event);
 };
 
@@ -264,8 +264,8 @@ Blockly.BlockDragger.prototype.endBlockDrag = function(e, currentDragDeltaXY) {
  * @private
  */
 Blockly.BlockDragger.prototype.fireDragEndEvent_ = function() {
-  var event = new Blockly.Events.BlockDrag(this.draggingBlock_, false,
-      this.draggingBlock_.getDescendants(false));
+  var event = new (Blockly.Events.get(Blockly.Events.BLOCK_DRAG))(
+      this.draggingBlock_, false, this.draggingBlock_.getDescendants(false));
   Blockly.Events.fire(event);
 };
 
@@ -274,7 +274,8 @@ Blockly.BlockDragger.prototype.fireDragEndEvent_ = function() {
  * @private
  */
 Blockly.BlockDragger.prototype.fireMoveEvent_ = function() {
-  var event = new Blockly.Events.BlockMove(this.draggingBlock_);
+  var event = new (Blockly.Events.get(Blockly.Events.BLOCK_MOVE))(
+      this.draggingBlock_);
   event.oldCoordinate = this.startXY_;
   event.recordNew();
   Blockly.Events.fire(event);
diff --git a/core/block_svg.js b/core/block_svg.js
index 55c8673df..49b68ff23 100644
--- a/core/block_svg.js
+++ b/core/block_svg.js
@@ -35,6 +35,7 @@ goog.require('Blockly.utils.dom');
 goog.require('Blockly.utils.object');
 goog.require('Blockly.utils.Rect');
 goog.require('Blockly.utils.userAgent');
+goog.require('Blockly.Xml');
 
 goog.requireType('Blockly.blockRendering.Debug');
 goog.requireType('Blockly.Comment');
@@ -310,7 +311,8 @@ Blockly.BlockSvg.prototype.select = function() {
       Blockly.Events.enable();
     }
   }
-  var event = new Blockly.Events.Selected(oldId, this.id, this.workspace.id);
+  var event = new (Blockly.Events.get(Blockly.Events.SELECTED))(oldId, this.id,
+      this.workspace.id);
   Blockly.Events.fire(event);
   Blockly.selected = this;
   this.addSelect();
@@ -323,7 +325,8 @@ Blockly.BlockSvg.prototype.unselect = function() {
   if (Blockly.selected != this) {
     return;
   }
-  var event = new Blockly.Events.Selected(this.id, null, this.workspace.id);
+  var event = new (Blockly.Events.get(Blockly.Events.SELECTED))(this.id, null,
+      this.workspace.id);
   event.workspaceId = this.workspace.id;
   Blockly.Events.fire(event);
   Blockly.selected = null;
@@ -464,7 +467,7 @@ Blockly.BlockSvg.prototype.moveBy = function(dx, dy) {
   }
   var eventsEnabled = Blockly.Events.isEnabled();
   if (eventsEnabled) {
-    var event = new Blockly.Events.BlockMove(this);
+    var event = new (Blockly.Events.get(Blockly.Events.BLOCK_MOVE))(this);
   }
   var xy = this.getRelativeToSurfaceXY();
   this.translate(xy.x + dx, xy.y + dy);
diff --git a/core/blockly.js b/core/blockly.js
index bcc24671a..36902a643 100644
--- a/core/blockly.js
+++ b/core/blockly.js
@@ -19,6 +19,9 @@ goog.provide('Blockly');
 goog.require('Blockly.constants');
 goog.require('Blockly.browserEvents');
 goog.require('Blockly.Events');
+goog.require('Blockly.Events.BlockCreate');
+goog.require('Blockly.Events.FinishedLoading');
+goog.require('Blockly.Events.VarCreate');
 goog.require('Blockly.Events.Ui');
 goog.require('Blockly.Events.UiBase');
 goog.require('Blockly.inject');
diff --git a/core/bubble_dragger.js b/core/bubble_dragger.js
index 8caf7c8cb..17d59f8be 100644
--- a/core/bubble_dragger.js
+++ b/core/bubble_dragger.js
@@ -229,7 +229,7 @@ Blockly.BubbleDragger.prototype.endBubbleDrag = function(
  */
 Blockly.BubbleDragger.prototype.fireMoveEvent_ = function() {
   if (this.draggingBubble_.isComment) {
-    var event = new Blockly.Events.CommentMove(
+    var event = new (Blockly.Events.get(Blockly.Events.COMMENT_MOVE))(
         /** @type {!Blockly.WorkspaceCommentSvg} */ (this.draggingBubble_));
     event.setOldCoordinate(this.startXY_);
     event.recordNew();
diff --git a/core/comment.js b/core/comment.js
index b8063d158..6330f1d10 100644
--- a/core/comment.js
+++ b/core/comment.js
@@ -178,8 +178,10 @@ Blockly.Comment.prototype.createEditor_ = function() {
   this.onChangeWrapper_ = Blockly.browserEvents.conditionalBind(
       textarea, 'change', this, function(_e) {
         if (this.cachedText_ != this.model_.text) {
-          Blockly.Events.fire(new Blockly.Events.BlockChange(
-              this.block_, 'comment', null, this.cachedText_, this.model_.text));
+          Blockly.Events.fire(
+              new (Blockly.Events.get(Blockly.Events.BLOCK_CHANGE))(
+                  this.block_, 'comment', null, this.cachedText_,
+                  this.model_.text));
         }
       });
   this.onInputWrapper_ = Blockly.browserEvents.conditionalBind(
@@ -242,8 +244,8 @@ Blockly.Comment.prototype.setVisible = function(visible) {
   if (visible == this.isVisible()) {
     return;
   }
-  Blockly.Events.fire(
-      new Blockly.Events.BubbleOpen(this.block_, visible, 'comment'));
+  Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.BUBBLE_OPEN))(
+      this.block_, visible, 'comment'));
   this.model_.pinned = visible;
   if (visible) {
     this.createBubble_();
diff --git a/core/connection.js b/core/connection.js
index 249e434e6..988f48b34 100644
--- a/core/connection.js
+++ b/core/connection.js
@@ -188,7 +188,7 @@ Blockly.Connection.prototype.connect_ = function(childConnection) {
 
   var event;
   if (Blockly.Events.isEnabled()) {
-    event = new Blockly.Events.BlockMove(childBlock);
+    event = new (Blockly.Events.get(Blockly.Events.BLOCK_MOVE))(childBlock);
   }
   // Establish the connections.
   Blockly.Connection.connectReciprocally_(parentConnection, childConnection);
@@ -466,7 +466,7 @@ Blockly.Connection.prototype.disconnectInternal_ = function(parentBlock,
     childBlock) {
   var event;
   if (Blockly.Events.isEnabled()) {
-    event = new Blockly.Events.BlockMove(childBlock);
+    event = new (Blockly.Events.get(Blockly.Events.BLOCK_MOVE))(childBlock);
   }
   var otherConnection = this.targetConnection;
   otherConnection.targetConnection = null;
diff --git a/core/contextmenu.js b/core/contextmenu.js
index 16d711154..74501de62 100644
--- a/core/contextmenu.js
+++ b/core/contextmenu.js
@@ -203,7 +203,8 @@ Blockly.ContextMenu.callbackFactory = function(block, xml) {
       Blockly.Events.enable();
     }
     if (Blockly.Events.isEnabled() && !newBlock.isShadow()) {
-      Blockly.Events.fire(new Blockly.Events.BlockCreate(newBlock));
+      Blockly.Events.fire(
+          new (Blockly.Events.get(Blockly.Events.BLOCK_CREATE))(newBlock));
     }
     newBlock.select();
   };
diff --git a/core/contextmenu_items.js b/core/contextmenu_items.js
index a33126d02..11a8332bb 100644
--- a/core/contextmenu_items.js
+++ b/core/contextmenu_items.js
@@ -17,6 +17,7 @@
 goog.provide('Blockly.ContextMenuItems');
 
 goog.require('Blockly.constants');
+goog.require('Blockly.Events');
 
 goog.requireType('Blockly.BlockSvg');
 
diff --git a/core/events/block_events.js b/core/events/block_events.js
index d6b9f80c5..cbc608f3e 100644
--- a/core/events/block_events.js
+++ b/core/events/block_events.js
@@ -26,8 +26,7 @@ goog.require('Blockly.registry');
 goog.require('Blockly.utils.Coordinate');
 goog.require('Blockly.utils.object');
 goog.require('Blockly.utils.xml');
-// TODO: Fix recursive dependency.
-// goog.require('Blockly.Xml');
+goog.require('Blockly.Xml');
 
 goog.requireType('Blockly.Block');
 
@@ -202,7 +201,7 @@ Blockly.Events.Change.prototype.run = function(forward) {
         var dom = Blockly.Xml.textToDom(/** @type {string} */ (value) || '<mutation/>');
         block.domToMutation(dom);
       }
-      Blockly.Events.fire(new Blockly.Events.Change(
+      Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.CHANGE))(
           block, 'mutation', null, oldMutation, value));
       break;
     default:
diff --git a/core/events/events.js b/core/events/events.js
index c1991692c..70b1365c6 100644
--- a/core/events/events.js
+++ b/core/events/events.js
@@ -399,8 +399,7 @@ Blockly.Events.getDescendantIds = function(block) {
  * @throws {Error} if an event type is not found in the registry.
  */
 Blockly.Events.fromJson = function(json, workspace) {
-  var eventClass = Blockly.registry.getClass(Blockly.registry.Type.EVENT,
-      json.type);
+  var eventClass = Blockly.Events.get(json.type);
   if (!eventClass) {
     throw Error('Unknown event type.');
   }
@@ -410,6 +409,16 @@ Blockly.Events.fromJson = function(json, workspace) {
   return event;
 };
 
+/**
+ * Gets the class for a specific event type from the registry.
+ * @param {string} eventType The type of the event to get.
+ * @return {?function(new:Blockly.Events.Abstract, ...?)} The event class with
+ *     the given type or null if none exists.
+ */
+Blockly.Events.get = function(eventType) {
+  return Blockly.registry.getClass(Blockly.registry.Type.EVENT, eventType);
+};
+
 /**
  * Enable/disable a block depending on whether it is properly connected.
  * Use this on applications where all blocks should be connected to a top block.
diff --git a/core/events/ws_comment_events.js b/core/events/ws_comment_events.js
index 6a5d0b4f2..5bcfa4758 100644
--- a/core/events/ws_comment_events.js
+++ b/core/events/ws_comment_events.js
@@ -22,8 +22,7 @@ goog.require('Blockly.registry');
 goog.require('Blockly.utils.Coordinate');
 goog.require('Blockly.utils.object');
 goog.require('Blockly.utils.xml');
-// TODO: Fix recursive dependency.
-// goog.require('Blockly.Xml');
+goog.require('Blockly.Xml');
 
 
 /**
diff --git a/core/field.js b/core/field.js
index f9c30937f..d179aba85 100644
--- a/core/field.js
+++ b/core/field.js
@@ -831,7 +831,7 @@ Blockly.Field.prototype.setValue = function(newValue) {
   }
 
   if (source && Blockly.Events.isEnabled()) {
-    Blockly.Events.fire(new Blockly.Events.BlockChange(
+    Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.BLOCK_CHANGE))(
         source, 'field', this.name || null, oldValue, newValue));
   }
   this.doValueUpdate_(newValue);
diff --git a/core/field_dropdown.js b/core/field_dropdown.js
index d877f6cab..38758c3b1 100644
--- a/core/field_dropdown.js
+++ b/core/field_dropdown.js
@@ -15,7 +15,6 @@
 goog.provide('Blockly.FieldDropdown');
 
 goog.require('Blockly.Events');
-goog.require('Blockly.Events.BlockChange');
 goog.require('Blockly.Field');
 goog.require('Blockly.fieldRegistry');
 goog.require('Blockly.Menu');
diff --git a/core/field_textinput.js b/core/field_textinput.js
index 9e1cb8d9f..4ee8673ba 100644
--- a/core/field_textinput.js
+++ b/core/field_textinput.js
@@ -203,7 +203,7 @@ Blockly.FieldTextInput.prototype.doValueInvalid_ = function(_invalidValue) {
     // Revert value when the text becomes invalid.
     this.value_ = this.htmlInput_.untypedDefaultValue_;
     if (this.sourceBlock_ && Blockly.Events.isEnabled()) {
-      Blockly.Events.fire(new Blockly.Events.BlockChange(
+      Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.BLOCK_CHANGE))(
           this.sourceBlock_, 'field', this.name || null, oldValue, this.value_));
     }
   }
diff --git a/core/flyout_base.js b/core/flyout_base.js
index 16c0266ad..acd067cff 100644
--- a/core/flyout_base.js
+++ b/core/flyout_base.js
@@ -28,6 +28,7 @@ goog.require('Blockly.utils.Coordinate');
 goog.require('Blockly.utils.dom');
 goog.require('Blockly.utils.Svg');
 goog.require('Blockly.utils.toolbox');
+goog.require('Blockly.utils.xml');
 goog.require('Blockly.WorkspaceSvg');
 goog.require('Blockly.Xml');
 
@@ -800,12 +801,14 @@ Blockly.Flyout.prototype.createBlock = function(originalBlock) {
     // Fire a VarCreate event for each (if any) new variable created.
     for (var i = 0; i < newVariables.length; i++) {
       var thisVariable = newVariables[i];
-      Blockly.Events.fire(new Blockly.Events.VarCreate(thisVariable));
+      Blockly.Events.fire(
+          new (Blockly.Events.get(Blockly.Events.VAR_CREATE))(thisVariable));
     }
 
     // Block events come after var events, in case they refer to newly created
     // variables.
-    Blockly.Events.fire(new Blockly.Events.Create(newBlock));
+    Blockly.Events.fire(
+        new (Blockly.Events.get(Blockly.Events.BLOCK_CREATE))(newBlock));
   }
   if (this.autoClose) {
     this.hide();
diff --git a/core/gesture.js b/core/gesture.js
index edbbba096..ab80c0cf8 100644
--- a/core/gesture.js
+++ b/core/gesture.js
@@ -654,8 +654,8 @@ Blockly.Gesture.prototype.handleWsStart = function(e, ws) {
  * @private
  */
 Blockly.Gesture.prototype.fireWorkspaceClick_ = function(ws) {
-  var clickEvent = new Blockly.Events.Click(null, ws.id, 'workspace');
-  Blockly.Events.fire(clickEvent);
+  Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.CLICK))(
+      null, ws.id, 'workspace'));
 };
 
 /**
@@ -745,7 +745,7 @@ Blockly.Gesture.prototype.doBlockClick_ = function() {
     }
   } else {
     // Clicks events are on the start block, even if it was a shadow.
-    var event = new Blockly.Events.Click(
+    var event = new (Blockly.Events.get(Blockly.Events.CLICK))(
         this.startBlock_, this.startWorkspace_.id, 'block');
     Blockly.Events.fire(event);
   }
diff --git a/core/inject.js b/core/inject.js
index 581e69e32..e15f49f6c 100644
--- a/core/inject.js
+++ b/core/inject.js
@@ -23,6 +23,7 @@ goog.require('Blockly.Options');
 goog.require('Blockly.ScrollbarPair');
 goog.require('Blockly.Tooltip');
 goog.require('Blockly.utils');
+goog.require('Blockly.utils.aria');
 goog.require('Blockly.utils.dom');
 goog.require('Blockly.utils.Svg');
 goog.require('Blockly.utils.userAgent');
diff --git a/core/keyboard_nav/basic_cursor.js b/core/keyboard_nav/basic_cursor.js
index c853fd9d9..e38031321 100644
--- a/core/keyboard_nav/basic_cursor.js
+++ b/core/keyboard_nav/basic_cursor.js
@@ -15,6 +15,7 @@ goog.provide('Blockly.BasicCursor');
 
 goog.require('Blockly.ASTNode');
 goog.require('Blockly.Cursor');
+goog.require('Blockly.registry');
 
 
 /**
diff --git a/core/keyboard_nav/cursor.js b/core/keyboard_nav/cursor.js
index 2ef225b90..de9b0b11c 100644
--- a/core/keyboard_nav/cursor.js
+++ b/core/keyboard_nav/cursor.js
@@ -15,6 +15,7 @@ goog.provide('Blockly.Cursor');
 
 goog.require('Blockly.ASTNode');
 goog.require('Blockly.Marker');
+goog.require('Blockly.registry');
 goog.require('Blockly.utils.object');
 
 goog.requireType('Blockly.ShortcutRegistry');
diff --git a/core/metrics_manager.js b/core/metrics_manager.js
index 6e135ac6e..9ca3fed0c 100644
--- a/core/metrics_manager.js
+++ b/core/metrics_manager.js
@@ -13,6 +13,7 @@
 goog.provide('Blockly.MetricsManager');
 
 goog.require('Blockly.IMetricsManager');
+goog.require('Blockly.registry');
 goog.require('Blockly.utils.Size');
 
 goog.requireType('Blockly.IFlyout');
diff --git a/core/mutator.js b/core/mutator.js
index 70c0bc111..416f77870 100644
--- a/core/mutator.js
+++ b/core/mutator.js
@@ -290,8 +290,8 @@ Blockly.Mutator.prototype.setVisible = function(visible) {
     // No change.
     return;
   }
-  Blockly.Events.fire(
-      new Blockly.Events.BubbleOpen(this.block_, visible, 'mutator'));
+  Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.BUBBLE_OPEN))(
+      this.block_, visible, 'mutator'));
   if (visible) {
     // Create the bubble.
     this.bubble_ = new Blockly.Bubble(
@@ -426,7 +426,7 @@ Blockly.Mutator.prototype.workspaceChanged_ = function(e) {
     var newMutationDom = block.mutationToDom();
     var newMutation = newMutationDom && Blockly.Xml.domToText(newMutationDom);
     if (oldMutation != newMutation) {
-      Blockly.Events.fire(new Blockly.Events.BlockChange(
+      Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.BLOCK_CHANGE))(
           block, 'mutation', null, oldMutation, newMutation));
       // Ensure that any bump is part of this mutation's event group.
       var group = Blockly.Events.getGroup();
diff --git a/core/procedures.js b/core/procedures.js
index 2fbd13134..890a2e3f8 100644
--- a/core/procedures.js
+++ b/core/procedures.js
@@ -378,7 +378,7 @@ Blockly.Procedures.mutateCallers = function(defBlock) {
       // undo action since it is deterministically tied to the procedure's
       // definition mutation.
       Blockly.Events.recordUndo = false;
-      Blockly.Events.fire(new Blockly.Events.BlockChange(
+      Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.BLOCK_CHANGE))(
           caller, 'mutation', null, oldMutation, newMutation));
       Blockly.Events.recordUndo = oldRecordUndo;
     }
diff --git a/core/renderers/common/marker_svg.js b/core/renderers/common/marker_svg.js
index 2d1f40560..8cee6f5e5 100644
--- a/core/renderers/common/marker_svg.js
+++ b/core/renderers/common/marker_svg.js
@@ -15,6 +15,7 @@ goog.provide('Blockly.blockRendering.MarkerSvg');
 
 goog.require('Blockly.ASTNode');
 goog.require('Blockly.constants');
+goog.require('Blockly.Events');
 goog.require('Blockly.Events.MarkerMove');
 goog.require('Blockly.utils.dom');
 goog.require('Blockly.utils.Svg');
@@ -561,7 +562,7 @@ Blockly.blockRendering.MarkerSvg.prototype.hide = function() {
 Blockly.blockRendering.MarkerSvg.prototype.fireMarkerEvent_ = function(
     oldNode, curNode) {
   var curBlock = curNode.getSourceBlock();
-  var event = new Blockly.Events.MarkerMove(
+  var event = new (Blockly.Events.get(Blockly.Events.MARKER_MOVE))(
       curBlock, this.isCursor(), oldNode, curNode);
   Blockly.Events.fire(event);
 };
diff --git a/core/scrollbar.js b/core/scrollbar.js
index 9b91f50ae..ba752a053 100644
--- a/core/scrollbar.js
+++ b/core/scrollbar.js
@@ -14,6 +14,7 @@ goog.provide('Blockly.Scrollbar');
 goog.provide('Blockly.ScrollbarPair');
 
 goog.require('Blockly.browserEvents');
+goog.require('Blockly.Events');
 goog.require('Blockly.Touch');
 goog.require('Blockly.utils');
 goog.require('Blockly.utils.Coordinate');
diff --git a/core/toolbox/toolbox.js b/core/toolbox/toolbox.js
index 8201812b7..775f2e937 100644
--- a/core/toolbox/toolbox.js
+++ b/core/toolbox/toolbox.js
@@ -818,7 +818,7 @@ Blockly.Toolbox.prototype.fireSelectEvent_ = function(oldItem, newItem) {
   if (oldItem == newItem) {
     newElement = null;
   }
-  var event = new Blockly.Events.ToolboxItemSelect(
+  var event = new (Blockly.Events.get(Blockly.Events.TOOLBOX_ITEM_SELECT))(
       oldElement, newElement, this.workspace_.id);
   Blockly.Events.fire(event);
 };
diff --git a/core/trashcan.js b/core/trashcan.js
index 9231eab52..e47571145 100644
--- a/core/trashcan.js
+++ b/core/trashcan.js
@@ -14,6 +14,7 @@ goog.provide('Blockly.Trashcan');
 
 goog.require('Blockly.browserEvents');
 goog.require('Blockly.constants');
+goog.require('Blockly.Events');
 goog.require('Blockly.Events.TrashcanOpen');
 goog.require('Blockly.Scrollbar');
 goog.require('Blockly.utils.dom');
@@ -568,8 +569,8 @@ Blockly.Trashcan.prototype.click = function() {
  * @private
  */
 Blockly.Trashcan.prototype.fireUiEvent_ = function(trashcanOpen) {
-  var uiEvent =
-      new Blockly.Events.TrashcanOpen(trashcanOpen,this.workspace_.id);
+  var uiEvent = new (Blockly.Events.get(Blockly.Events.TRASHCAN_OPEN))(
+      trashcanOpen,this.workspace_.id);
   Blockly.Events.fire(uiEvent);
 };
 
diff --git a/core/utils/toolbox.js b/core/utils/toolbox.js
index 563e6eb53..5340562a0 100644
--- a/core/utils/toolbox.js
+++ b/core/utils/toolbox.js
@@ -13,6 +13,7 @@
 goog.provide('Blockly.utils.toolbox');
 
 goog.require('Blockly.constants');
+goog.require('Blockly.Xml');
 
 goog.requireType('Blockly.ToolboxCategory');
 goog.requireType('Blockly.ToolboxSeparator');
diff --git a/core/variable_map.js b/core/variable_map.js
index c05f74b86..5b01af204 100644
--- a/core/variable_map.js
+++ b/core/variable_map.js
@@ -106,7 +106,8 @@ Blockly.VariableMap.prototype.renameVariableById = function(id, newName) {
  */
 Blockly.VariableMap.prototype.renameVariableAndUses_ = function(variable,
     newName, blocks) {
-  Blockly.Events.fire(new Blockly.Events.VarRename(variable, newName));
+  Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.VAR_RENAME))(
+      variable, newName));
   variable.name = newName;
   for (var i = 0; i < blocks.length; i++) {
     blocks[i].updateVarName(variable);
@@ -143,7 +144,8 @@ Blockly.VariableMap.prototype.renameVariableWithConflict_ = function(variable,
   }
 
   // Finally delete the original variable, which is now unreferenced.
-  Blockly.Events.fire(new Blockly.Events.VarDelete(variable));
+  Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.VAR_DELETE))(
+      variable));
   // And remove it from the list.
   var variableList = this.getVariablesOfType(type);
   var variableIndex = variableList.indexOf(variable);
@@ -205,7 +207,8 @@ Blockly.VariableMap.prototype.deleteVariable = function(variable) {
   for (var i = 0, tempVar; (tempVar = variableList[i]); i++) {
     if (tempVar.getId() == variable.getId()) {
       variableList.splice(i, 1);
-      Blockly.Events.fire(new Blockly.Events.VarDelete(variable));
+      Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.VAR_DELETE))(
+          variable));
       return;
     }
   }
diff --git a/core/variable_model.js b/core/variable_model.js
index c92ed85a0..036c99e5c 100644
--- a/core/variable_model.js
+++ b/core/variable_model.js
@@ -66,7 +66,8 @@ Blockly.VariableModel = function(workspace, name, opt_type, opt_id) {
    */
   this.id_ = opt_id || Blockly.utils.genUid();
 
-  Blockly.Events.fire(new Blockly.Events.VarCreate(this));
+  Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.VAR_CREATE))(
+      this));
 };
 
 /**
diff --git a/core/warning.js b/core/warning.js
index ca5385bea..1adfae2e7 100644
--- a/core/warning.js
+++ b/core/warning.js
@@ -86,8 +86,8 @@ Blockly.Warning.prototype.setVisible = function(visible) {
   if (visible == this.isVisible()) {
     return;
   }
-  Blockly.Events.fire(
-      new Blockly.Events.BubbleOpen(this.block_, visible, 'warning'));
+  Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.BUBBLE_OPEN))(
+      this.block_, visible, 'warning'));
   if (visible) {
     this.createBubble_();
   } else {
diff --git a/core/workspace.js b/core/workspace.js
index ec89c0078..7d3fa4e47 100644
--- a/core/workspace.js
+++ b/core/workspace.js
@@ -15,6 +15,7 @@ goog.provide('Blockly.Workspace');
 goog.require('Blockly.ConnectionChecker');
 goog.require('Blockly.Events');
 goog.require('Blockly.Options');
+goog.require('Blockly.registry');
 goog.require('Blockly.utils');
 goog.require('Blockly.utils.math');
 goog.require('Blockly.VariableMap');
diff --git a/core/workspace_comment.js b/core/workspace_comment.js
index 3edaa4814..76934473b 100644
--- a/core/workspace_comment.js
+++ b/core/workspace_comment.js
@@ -116,7 +116,8 @@ Blockly.WorkspaceComment.prototype.dispose = function() {
   }
 
   if (Blockly.Events.isEnabled()) {
-    Blockly.Events.fire(new Blockly.Events.CommentDelete(this));
+    Blockly.Events.fire(
+        new (Blockly.Events.get(Blockly.Events.COMMENT_DELETE))(this));
   }
 
   // Remove from the list of top comments and the comment database.
@@ -180,7 +181,7 @@ Blockly.WorkspaceComment.prototype.getXY = function() {
  * @package
  */
 Blockly.WorkspaceComment.prototype.moveBy = function(dx, dy) {
-  var event = new Blockly.Events.CommentMove(this);
+  var event = new (Blockly.Events.get(Blockly.Events.COMMENT_MOVE))(this);
   this.xy_.translate(dx, dy);
   event.recordNew();
   Blockly.Events.fire(event);
@@ -257,8 +258,8 @@ Blockly.WorkspaceComment.prototype.getContent = function() {
  */
 Blockly.WorkspaceComment.prototype.setContent = function(content) {
   if (this.content_ != content) {
-    Blockly.Events.fire(
-        new Blockly.Events.CommentChange(this, this.content_, content));
+    Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.COMMENT_CHANGE))(
+        this, this.content_, content));
     this.content_ = content;
   }
 };
@@ -307,7 +308,8 @@ Blockly.WorkspaceComment.fireCreateEvent = function(comment) {
       Blockly.Events.setGroup(true);
     }
     try {
-      Blockly.Events.fire(new Blockly.Events.CommentCreate(comment));
+      Blockly.Events.fire(
+          new (Blockly.Events.get(Blockly.Events.COMMENT_CREATE))(comment));
     } finally {
       if (!existingGroup) {
         Blockly.Events.setGroup(false);
diff --git a/core/workspace_comment_svg.js b/core/workspace_comment_svg.js
index 68e100fc8..8b828d958 100644
--- a/core/workspace_comment_svg.js
+++ b/core/workspace_comment_svg.js
@@ -127,7 +127,8 @@ Blockly.WorkspaceCommentSvg.prototype.dispose = function() {
   }
 
   if (Blockly.Events.isEnabled()) {
-    Blockly.Events.fire(new Blockly.Events.CommentDelete(this));
+    Blockly.Events.fire(
+        new (Blockly.Events.get(Blockly.Events.COMMENT_DELETE))(this));
   }
 
   Blockly.utils.dom.removeNode(this.svgGroup_);
@@ -224,7 +225,8 @@ Blockly.WorkspaceCommentSvg.prototype.select = function() {
       Blockly.Events.enable();
     }
   }
-  var event = new Blockly.Events.Selected(oldId, this.id, this.workspace.id);
+  var event = new (Blockly.Events.get(Blockly.Events.SELECTED))(oldId, this.id,
+      this.workspace.id);
   Blockly.Events.fire(event);
   Blockly.selected = this;
   this.addSelect();
@@ -238,7 +240,8 @@ Blockly.WorkspaceCommentSvg.prototype.unselect = function() {
   if (Blockly.selected != this) {
     return;
   }
-  var event = new Blockly.Events.Selected(this.id, null, this.workspace.id);
+  var event = new (Blockly.Events.get(Blockly.Events.SELECTED))(this.id, null,
+      this.workspace.id);
   Blockly.Events.fire(event);
   Blockly.selected = null;
   this.removeSelect();
@@ -331,7 +334,7 @@ Blockly.WorkspaceCommentSvg.prototype.getRelativeToSurfaceXY = function() {
  * @package
  */
 Blockly.WorkspaceCommentSvg.prototype.moveBy = function(dx, dy) {
-  var event = new Blockly.Events.CommentMove(this);
+  var event = new (Blockly.Events.get(Blockly.Events.COMMENT_MOVE))(this);
   // TODO: Do I need to look up the relative to surface XY position here?
   var xy = this.getRelativeToSurfaceXY();
   this.translate(xy.x + dx, xy.y + dy);
diff --git a/core/workspace_svg.js b/core/workspace_svg.js
index 9e3023cd7..5a4401465 100644
--- a/core/workspace_svg.js
+++ b/core/workspace_svg.js
@@ -618,7 +618,8 @@ Blockly.WorkspaceSvg.prototype.refreshTheme = function() {
     this.setVisible(true);
   }
 
-  var event = new Blockly.Events.ThemeChange(this.getTheme().name, this.id);
+  var event = new (Blockly.Events.get(Blockly.Events.THEME_CHANGE))(
+      this.getTheme().name, this.id);
   Blockly.Events.fire(event);
 };
 
@@ -1163,7 +1164,8 @@ Blockly.WorkspaceSvg.prototype.maybeFireViewportChangeEvent = function() {
   this.oldScale_ = scale;
   this.oldTop_ = top;
   this.oldLeft_ = left;
-  var event = new Blockly.Events.ViewportChange(top, left, scale, this.id);
+  var event = new (Blockly.Events.get(Blockly.Events.VIEWPORT_CHANGE))(top,
+      left, scale, this.id);
   Blockly.Events.fire(event);
 };
 
@@ -1446,7 +1448,8 @@ Blockly.WorkspaceSvg.prototype.pasteBlock_ = function(xmlBlock) {
     Blockly.Events.enable();
   }
   if (Blockly.Events.isEnabled() && !block.isShadow()) {
-    Blockly.Events.fire(new Blockly.Events.BlockCreate(block));
+    Blockly.Events.fire(
+        new (Blockly.Events.get(Blockly.Events.BLOCK_CREATE))(block));
   }
   block.select();
 };
diff --git a/core/xml.js b/core/xml.js
index d8c382a9c..5aadaa894 100644
--- a/core/xml.js
+++ b/core/xml.js
@@ -18,9 +18,6 @@ goog.provide('Blockly.Xml');
 
 goog.require('Blockly.constants');
 goog.require('Blockly.Events');
-goog.require('Blockly.Events.BlockCreate');
-goog.require('Blockly.Events.FinishedLoading');
-goog.require('Blockly.Events.VarCreate');
 goog.require('Blockly.utils');
 goog.require('Blockly.utils.dom');
 goog.require('Blockly.utils.global');
@@ -481,7 +478,8 @@ Blockly.Xml.domToWorkspace = function(xml, workspace) {
   if (workspace.setResizesEnabled) {
     workspace.setResizesEnabled(true);
   }
-  Blockly.Events.fire(new Blockly.Events.FinishedLoading(workspace));
+  Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.FINISHED_LOADING))(
+      workspace));
   return newBlockIds;
 };
 
@@ -593,11 +591,13 @@ Blockly.Xml.domToBlock = function(xmlBlock, workspace) {
     // Fire a VarCreate event for each (if any) new variable created.
     for (var i = 0; i < newVariables.length; i++) {
       var thisVariable = newVariables[i];
-      Blockly.Events.fire(new Blockly.Events.VarCreate(thisVariable));
+      Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.VAR_CREATE))(
+          thisVariable));
     }
     // Block events come after var events, in case they refer to newly created
     // variables.
-    Blockly.Events.fire(new Blockly.Events.BlockCreate(topBlock));
+    Blockly.Events.fire(new (Blockly.Events.get(Blockly.Events.CREATE))(
+        topBlock));
   }
   return topBlock;
 };
diff --git a/core/zoom_controls.js b/core/zoom_controls.js
index f7e829e12..7383855c1 100644
--- a/core/zoom_controls.js
+++ b/core/zoom_controls.js
@@ -15,6 +15,8 @@ goog.provide('Blockly.ZoomControls');
 goog.require('Blockly.browserEvents');
 goog.require('Blockly.constants');
 goog.require('Blockly.Css');
+goog.require('Blockly.Events');
+goog.require('Blockly.Events.Click');
 goog.require('Blockly.Scrollbar');
 goog.require('Blockly.Touch');
 goog.require('Blockly.utils.dom');
@@ -424,7 +426,7 @@ Blockly.ZoomControls.prototype.resetZoom_ = function(e) {
  * @private
  */
 Blockly.ZoomControls.prototype.fireZoomEvent_ = function() {
-  var uiEvent = new Blockly.Events.Click(
+  var uiEvent = new (Blockly.Events.get(Blockly.Events.CLICK))(
       null, this.workspace_.id, 'zoom_controls');
   Blockly.Events.fire(uiEvent);
 };