Normalizing .dropEffect across platforms (specifically Windows).

chrome/browser/resources/ntp4/tile_page.js

Index: chrome/browser/resources/ntp4/tile_page.js
diff --git a/chrome/browser/resources/ntp4/tile_page.js b/chrome/browser/resources/ntp4/tile_page.js
index cf3a3bbdd3fd2c0714002e45b9ebaffb8136800f..b2b922288b4dfb650d869d8f7f8d550f5f7b5e60 100644
--- a/chrome/browser/resources/ntp4/tile_page.js
+++ b/chrome/browser/resources/ntp4/tile_page.js
@@ -158,7 +158,10 @@ cr.define('ntp4', function() {
       if (this.landedOnTrash) {
         this.dragClone.classList.add('deleting');
       } else if (this.tilePage) {
-        if (this.tilePage.selected && e.dataTransfer.dropEffect != 'copy') {
+        // HACK(dbeam): Until we fix dropEffect to the correct behavior it will

[csilv, 2011/09/13 18:57:24]

Change this to a TODO comment instead.

[Dan Beam, 2011/09/13 22:19:13]

Done.

+        // differ on windows - crbug.com/39399.  That's why we use the custom
+        // .tilePage.lastDropEffect_ instead of e.dataTransfer.dropEffect.
+        if (this.tilePage.selected && this.tilePage.lastDropEffect_ != 'copy') {
           // The drag clone can still be hidden from the last drag move event.
           this.dragClone.hidden = false;
           // The tile's contents may have moved following the respositioning;
@@ -927,9 +930,19 @@ cr.define('ntp4', function() {
       if (newDragIndex < 0 || newDragIndex >= this.tileElements_.length)
         newDragIndex = this.dragItemIndex_;
       this.updateDropIndicator_(newDragIndex);
+
+      this.lastDropEffect_ = e.dataTransfer.dropEffect;
     },
 
     /**
+     * Normalizing dropEffect until all platform's implementations agree.  Right
+     * now Windows resets the dropEffect on a 'drop' back to 'copy' (and
+     * disregards the previous state), so we're making a temporary shim to keep
+     * our own state for now based on each dragover.
+     */
+    lastDropEffect_: null,

[csilv, 2011/09/13 18:57:24]

Is it necessary to do this? (ie, wont the default value of undefined work?)

[Dan Beam, 2011/09/13 22:19:13]

Done.

+
+    /**
      * Performs all actions necessary when the user completes a drop.
      * @param {Event} e A mouseover event for the drag drop.
      */