BoxLayout now suports per-view margins.

ui/views/view.cc

 // 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.
 
 #define _USE_MATH_DEFINES // For VC++ to get M_PI. This has to be first.
 
 #include "ui/views/view.h"
 
 #include <algorithm>
 #include <cmath>
@@ skipping 50 matching lines @@
 #include "ui/views/widget/native_widget_private.h"
 #include "ui/views/widget/root_view.h"
 #include "ui/views/widget/tooltip_manager.h"
 #include "ui/views/widget/widget.h"
 
 #if defined(OS_WIN)
 #include "base/win/scoped_gdi_object.h"
 #include "ui/native_theme/native_theme_win.h"
 #endif
 
+DECLARE_EXPORTED_UI_CLASS_PROPERTY_TYPE(VIEWS_EXPORT, gfx::Insets*);
+
 namespace views {
 
 namespace {
 
 #if defined(OS_WIN)
 const bool kContextMenuOnMousePress = false;
 #else
 const bool kContextMenuOnMousePress = true;
 #endif
 
@@ skipping 2582 matching lines @@
 
   // Message the RootView to do the drag and drop. That way if we're removed
   // the RootView can detect it and avoid calling us back.
   gfx::Point widget_location(event.location());
   ConvertPointToWidget(this, &widget_location);
   widget->RunShellDrag(this, data, widget_location, drag_operations, source);
   // WARNING: we may have been deleted.
   return true;
 }
 
+DEFINE_OWNED_UI_CLASS_PROPERTY_KEY(gfx::Insets, kMarginsKey, nullptr);
+
 }  // namespace views