Make the extra padding around VectorIconButtons configurable.

ui/views/views_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_VIEWS_DELEGATE_H_
 #define UI_VIEWS_VIEWS_DELEGATE_H_
 
 #include <string>
 
 #if defined(OS_WIN)
@@ skipping 210 matching lines @@
 
   // Returns the default minimum width of a button.
   virtual int GetButtonMinimumWidth() const;
 
   // Returns the minimum width of a dialog button.
   virtual int GetDialogButtonMinimumWidth() const;
 
   // Returns the default padding to add on each side of a button's label.
   virtual int GetButtonHorizontalPadding() const;
 
+  // Returns the margins that should be placed around a button's content.
+  virtual gfx::Insets GetButtonMargins() const;
+
  protected:
   ViewsDelegate();
 
  private:
   std::unique_ptr<ViewsTouchEditingControllerFactory> views_tsc_factory_;
 
 #if defined(USE_AURA)
   std::unique_ptr<TouchSelectionMenuRunnerViews> touch_selection_menu_runner_;
 #endif
 
   NativeWidgetFactory native_widget_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ViewsDelegate);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_VIEWS_DELEGATE_H_