From 8f601345bb004b99dcfeb782744de680bd064c6b Mon Sep 17 00:00:00 2001
From: Rachel Fenichel <fenichel@google.com>
Date: Fri, 17 Jun 2016 12:39:18 -0700
Subject: [PATCH] cache delete areas instead of recalculating them onMouseDown

---
 core/block_svg.js     | 1 -
 core/flyout.js        | 4 ++++
 core/toolbox.js       | 4 ++++
 core/trashcan.js      | 4 ++++
 core/workspace_svg.js | 3 +++
 5 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/core/block_svg.js b/core/block_svg.js
index 8fc64f3a8..c1f2b8df6 100644
--- a/core/block_svg.js
+++ b/core/block_svg.js
@@ -535,7 +535,6 @@ Blockly.BlockSvg.prototype.onMouseDown_ = function(e) {
   Blockly.terminateDrag_();
   this.select();
   Blockly.hideChaff();
-  this.workspace.recordDeleteAreas();
   if (Blockly.isRightButton(e)) {
     // Right-click.
     this.showContextMenu_(e);
diff --git a/core/flyout.js b/core/flyout.js
index 66d5c2c6e..85aaee983 100644
--- a/core/flyout.js
+++ b/core/flyout.js
@@ -952,6 +952,10 @@ Blockly.Flyout.prototype.filterForCapacity_ = function() {
  * @return {goog.math.Rect} Rectangle in which to delete.
  */
 Blockly.Flyout.prototype.getClientRect = function() {
+  if (!this.svgGroup_) {
+    return null;
+  }
+
   var flyoutRect = this.svgGroup_.getBoundingClientRect();
   // BIG_NUM is offscreen padding so that blocks dragged beyond the shown flyout
   // area are still deleted.  Must be larger than the largest screen size,
diff --git a/core/toolbox.js b/core/toolbox.js
index d9ca56dcc..b5b27f869 100644
--- a/core/toolbox.js
+++ b/core/toolbox.js
@@ -390,6 +390,10 @@ Blockly.Toolbox.prototype.clearSelection = function() {
  * @return {goog.math.Rect} Rectangle in which to delete.
  */
 Blockly.Toolbox.prototype.getClientRect = function() {
+  if (!this.HtmlDiv) {
+    return null;
+  }
+
   // BIG_NUM is offscreen padding so that blocks dragged beyond the toolbox
   // area are still deleted.  Must be smaller than Infinity, but larger than
   // the largest screen size.
diff --git a/core/trashcan.js b/core/trashcan.js
index 0a2954308..28baa0f20 100644
--- a/core/trashcan.js
+++ b/core/trashcan.js
@@ -265,6 +265,10 @@ Blockly.Trashcan.prototype.position = function() {
  * @return {goog.math.Rect} Rectangle in which to delete.
  */
 Blockly.Trashcan.prototype.getClientRect = function() {
+  if (!this.svgGroup_) {
+    return null;
+  }
+
   var trashRect = this.svgGroup_.getBoundingClientRect();
   var left = trashRect.left + this.SPRITE_LEFT_ - this.MARGIN_HOTSPOT_;
   var top = trashRect.top + this.SPRITE_TOP_ - this.MARGIN_HOTSPOT_;
diff --git a/core/workspace_svg.js b/core/workspace_svg.js
index de636a7a2..95150df19 100644
--- a/core/workspace_svg.js
+++ b/core/workspace_svg.js
@@ -211,6 +211,7 @@ Blockly.WorkspaceSvg.prototype.createDom = function(opt_backgroundClass) {
     this.addFlyout_();
   }
   this.updateGridPattern_();
+  this.recordDeleteAreas();
   return this.svgGroup_;
 };
 
@@ -355,6 +356,8 @@ Blockly.WorkspaceSvg.prototype.resize = function() {
   if (this.scrollbar) {
     this.scrollbar.resize();
   }
+
+  this.recordDeleteAreas();
 };
 
 /**