Fix a comment in the GridLayout explanation (refer to column set rather than colum).

ui/views/layout/grid_layout.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef UI_VIEWS_LAYOUT_GRID_LAYOUT_H_
 #define UI_VIEWS_LAYOUT_GRID_LAYOUT_H_
 
 #include <stddef.h>
 
 #include <vector>
 
 #include "base/macros.h"
 #include "ui/gfx/geometry/insets.h"
 #include "ui/gfx/geometry/size.h"
 #include "ui/views/layout/layout_manager.h"
 
 // GridLayout is a LayoutManager that positions child Views in a grid. You
 // define the structure of the Grid first, then add the Views.
 // The following creates a trivial grid with two columns separated by
 // a column with padding:
-// ColumnSet* columns = layout->AddColumnSet(0); // Give this column an
+// ColumnSet* columns = layout->AddColumnSet(0); // Give this column set an
 //                                               // identifier of 0.
 // columns->AddColumn(FILL, // Views are horizontally resized to fill column.
 //                    FILL, // Views starting in this column are vertically
 //                          // resized.
 //                    1,    // This column has a resize weight of 1.
 //                    USE_PREF, // Use the preferred size of the view.
 //                    0,   // Ignored for USE_PREF.
 //                    0);  // A minimum width of 0.
 // columns->AddPaddingColumn(0,   // The padding column is not resizable.
 //                           10); // And has a width of 10 pixels.
@@ skipping 335 matching lines @@
   // The master column of those columns that are linked. See Column
   // for a description of what the master column is.
   std::vector<Column*> master_columns_;
 
   DISALLOW_COPY_AND_ASSIGN(ColumnSet);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_LAYOUT_GRID_LAYOUT_H_