Improve scroll performance of WebInspector.TreeOutlineDataGridSynchronizer.

https://bugs.webkit.org/show_bug.cgi?id=126660

Reviewed by Joseph Pecoraro.

* UserInterface/TreeOutlineDataGridSynchronizer.js:
(WebInspector.TreeOutlineDataGridSynchronizer.prototype._treeOutlineScrolled):
(WebInspector.TreeOutlineDataGridSynchronizer.prototype._dataGridScrolled):
Ignore scroll events triggered by our internal use of setting scrollTop.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@162406 268f45cc-cd09-0410-ab3c-d52691b4dbfc

Source/WebInspectorUI/ChangeLog

+2014-01-08  Timothy Hatcher  <timothy@apple.com>
+
+        Improve scroll performance of WebInspector.TreeOutlineDataGridSynchronizer.
+
+        https://bugs.webkit.org/show_bug.cgi?id=126660
+
+        Reviewed by Joseph Pecoraro.
+
+        * UserInterface/TreeOutlineDataGridSynchronizer.js:
+        (WebInspector.TreeOutlineDataGridSynchronizer.prototype._treeOutlineScrolled):
+        (WebInspector.TreeOutlineDataGridSynchronizer.prototype._dataGridScrolled):
+        Ignore scroll events triggered by our internal use of setting scrollTop.
+
 2013-11-15  Timothy Hatcher  <timothy@apple.com>
 
         Add a synchronized DataGrid to the OverviewTimelineView.

Source/WebInspectorUI/UserInterface/TreeOutlineDataGridSynchronizer.js

@@ -112,11 +112,23 @@ WebInspector.TreeOutlineDataGridSynchronizer.prototype = {
 
     _treeOutlineScrolled: function(event)
     {
+        if (this._ignoreNextTreeOutlineScrollEvent) {
+            delete this._ignoreNextTreeOutlineScrollEvent;
+            return;
+        }
+
+        this._ignoreNextDataGridScrollEvent = true;
         this._dataGrid.scrollContainer.scrollTop = this._treeOutline.element.parentNode.scrollTop;
     },
 
     _dataGridScrolled: function(event)
     {
+        if (this._ignoreNextDataGridScrollEvent) {
+            delete this._ignoreNextDataGridScrollEvent;
+            return;
+        }
+
+        this._ignoreNextTreeOutlineScrollEvent = true;
         this._treeOutline.element.parentNode.scrollTop = this._dataGrid.scrollContainer.scrollTop;
     },