Increase warning level to 4 on Visual Studio

views/controls/table/native_table_win.cc

 // Copyright (c) 2011 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.
 
 #include "views/controls/table/native_table_win.h"
 
 #include <commctrl.h>
 #include <windowsx.h>
 
 #include "base/logging.h"
@@ skipping 568 matching lines @@
     }
   }
 
   memset(&item, 0, sizeof(LVITEM));
   item.stateMask = 0;
   item.mask = LVIF_TEXT;
   if (table_->type() == ICON_AND_TEXT)
     item.mask |= LVIF_IMAGE;
 
   for (size_t j = start_column; j < table_->GetVisibleColumnCount(); ++j) {
-    TableColumn& col = table_->GetVisibleColumnAt(j);
+    TableColumn col = table_->GetVisibleColumnAt(j);
     int max_text_width = ListView_GetStringWidth(native_view(),
                                                  col.title.c_str());
     for (int i = start; i < max_row; ++i) {
       item.iItem = i;
       item.iSubItem = j;
       std::wstring text = table_->model()->GetText(i, col.id);
       item.pszText = const_cast<LPWSTR>(text.c_str());
       item.iImage = 0;
       ListView_SetItem(native_view(), &item);
 
@@ skipping 303 matching lines @@
 
 ////////////////////////////////////////////////////////////////////////////////
 // NativeButtonWrapper, public:
 
 // static
 NativeTableWrapper* NativeTableWrapper::CreateNativeWrapper(TableView2* table) {
   return new NativeTableWin(table);
 }
 
 }  // namespace views