CPTableView: When columns or rows dragging ends, enqueue the dragged views so they can be available when you drag again the column if they haven't been unloaded before.

The 2nd time you drag the same column/row, reduces -dragViewFor... duration by 90% according to webkit profiling.

AppKit/CPTableHeaderView.j

@@ -486,6 +486,8 @@ var _CPTableColumnHeaderViewStringValueKey = @"_CPTableColumnHeaderViewStringVal
     [self stopTrackingTableColumn:_activeColumn at:aLocation];
 
     [self setNeedsDisplay:YES];
+    
+    [_tableView _enqueueDraggingViews];
 }
 
 - (BOOL)shouldResizeTableColumn:(int)aColumnIndex at:(CGPoint)aPoint

AppKit/CPTableView.j

@@ -235,6 +235,7 @@ CPTableViewFirstColumnOnlyAutoresizingStyle = 5;
     CPDragOperation     _dragOperationDefaultMask;
     int                 _retargetedDropRow;
     CPDragOperation     _retargetedDropOperation;
+    CPArray             _draggingViews;
 
     BOOL                _disableAutomaticResizing @accessors(property=disableAutomaticResizing);
     BOOL                _lastColumnShouldSnap;
@@ -357,6 +358,7 @@ CPTableViewFirstColumnOnlyAutoresizingStyle = 5;
     [self addSubview:_tableDrawView];
 
     _draggedColumn = nil;
+    _draggingViews = [CPArray array];
 
 /*      //gradients for the source list when CPTableView is NOT first responder or the window is NOT key
     // FIX ME: we need to actually implement this.
@@ -2833,7 +2835,8 @@ Your delegate can implement this method to avoid subclassing the tableview to ad
             [tableColumn _prepareDataView:dataView forRow:row];
 
             [view addSubview:dataView];
-
+            [_draggingViews addObject:dataView];
+            
             row = [theDraggedRows indexGreaterThanIndex:row];
         }
     }
@@ -2874,6 +2877,7 @@ Your delegate can implement this method to avoid subclassing the tableview to ad
 
         [dataView setObjectValue:[self _objectValueForTableColumn:tableColumn row:row]];
         [dragView addSubview:dataView];
+        [_draggingViews addObject:dataView];
 
         row = [_exposedRows indexGreaterThanIndex:row];
     }
@@ -4248,6 +4252,7 @@ Your delegate can implement this method to avoid subclassing the tableview to ad
     _retargetedDropRow = nil;
     _draggedRowIndexes = [CPIndexSet indexSet];
     [_dropOperationFeedbackView removeFromSuperview];
+    [self _enqueueDraggingViews];
 }
 
 /*
@@ -4436,6 +4441,16 @@ Your delegate can implement this method to avoid subclassing the tableview to ad
     [self draggedImage:aView endedAt:aLocation operation:anOperation];
 }
 
+- (void)_enqueueDraggingViews
+{
+    [_draggingViews enumerateObjectsUsingBlock:function(dataView, idx)
+    {
+        [self _enqueueReusableDataView:dataView];
+    }];
+    
+    [_draggingViews removeAllObjects];
+}
+
 /*!
     @ignore
 */