Add Vector2d classes that represent offsets, instead of using Point.

chrome/browser/ui/gtk/bookmarks/bookmark_bar_gtk.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.
 
 #include "chrome/browser/ui/gtk/bookmarks/bookmark_bar_gtk.h"
 
 #include <vector>
 
 #include "base/bind.h"
 #include "base/debug/trace_event.h"
@@ skipping 1158 matching lines @@
 
   drag_icon_ = bookmark_utils::GetDragRepresentationForNode(
       node, model_, theme_service_);
 
   // We have to jump through some hoops to get the drag icon to line up because
   // it is a different size than the button.
   GtkRequisition req;
   gtk_widget_size_request(drag_icon_, &req);
   gfx::Rect button_rect = gtk_util::WidgetBounds(button);
   gfx::Point drag_icon_relative =
-      gfx::Rect(req.width, req.height).CenterPoint().Add(
-          (last_pressed_coordinates_.Subtract(button_rect.CenterPoint())));
+      gfx::Rect(req.width, req.height).CenterPoint() +
+      (last_pressed_coordinates_ - button_rect.CenterPoint());
   gtk_drag_set_icon_widget(drag_context, drag_icon_,
                            drag_icon_relative.x(),
                            drag_icon_relative.y());
 
   // Hide our node, but reserve space for it on the toolbar.
   int index = gtk_toolbar_get_item_index(GTK_TOOLBAR(bookmark_toolbar_.get()),
                                          GTK_TOOL_ITEM(button_parent));
   gtk_widget_hide(button);
   toolbar_drop_item_ = CreateBookmarkToolItem(dragged_node_);
   g_object_ref_sink(GTK_OBJECT(toolbar_drop_item_));
@@ skipping 266 matching lines @@
 void BookmarkBarGtk::OnEditBookmarksEnabledChanged() {
   GtkDestDefaults dest_defaults =
       *edit_bookmarks_enabled_ ? GTK_DEST_DEFAULT_ALL :
                                  GTK_DEST_DEFAULT_DROP;
   gtk_drag_dest_set(overflow_button_, dest_defaults, NULL, 0, kDragAction);
   gtk_drag_dest_set(other_bookmarks_button_, dest_defaults,
                     NULL, 0, kDragAction);
   ui::SetDestTargetList(overflow_button_, kDestTargetList);
   ui::SetDestTargetList(other_bookmarks_button_, kDestTargetList);
 }