[Views] Allow dialog delegates to use a custom padding for the extra view

ui/views/window/dialog_delegate.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_WINDOW_DIALOG_DELEGATE_H_
 #define UI_VIEWS_WINDOW_DIALOG_DELEGATE_H_
 
 #include "base/compiler_specific.h"
 #include "base/strings/string16.h"
 #include "ui/accessibility/ax_enums.h"
@@ skipping 31 matching lines @@
   // a default location is used.
   static Widget* CreateDialogWidgetWithBounds(WidgetDelegate* delegate,
                                               gfx::NativeWindow context,
                                               gfx::NativeView parent,
                                               const gfx::Rect& bounds);
 
   // Override this function to display an extra view adjacent to the buttons.
   // Overrides may construct the view; this will only be called once per dialog.
   virtual View* CreateExtraView();
 
+  // Override this function to adjust the padding between the extra view and
+  // the confirm/cancel buttons. Note that if there are no buttons, this will
+  // not be used.
+  // If a custom padding should be used, returns true and populates |padding|.
+  virtual bool GetExtraViewPadding(int* padding);
+
   // Override this function to display an extra view in the titlebar.
   // Overrides may construct the view; this will only be called once per dialog.
   // Note: this only works for new style dialogs.
   virtual View* CreateTitlebarExtraView();
 
   // Override this function to display a footnote view below the buttons.
   // Overrides may construct the view; this will only be called once per dialog.
   virtual View* CreateFootnoteView();
 
   // For Dialog boxes, if there is a "Cancel" button or no dialog button at all,
@@ skipping 78 matching lines @@
   void ViewHierarchyChanged(
       const ViewHierarchyChangedDetails& details) override;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(DialogDelegateView);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WINDOW_DIALOG_DELEGATE_H_