Add VectorIconButton functionality to ImageButton.

ui/views/controls/button/image_button.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_CONTROLS_BUTTON_IMAGE_BUTTON_H_
 #define UI_VIEWS_CONTROLS_BUTTON_IMAGE_BUTTON_H_
 
 #include <memory>
 
 #include "base/gtest_prod_util.h"
@@ skipping 55 matching lines @@
   // will be at least this size, but may be larger if the image itself is
   // larger.
   const gfx::Size& minimum_image_size() const { return minimum_image_size_; }
   void SetMinimumImageSize(const gfx::Size& size);
 
   // Whether we should draw our images resources horizontally flipped.
   void SetDrawImageMirrored(bool mirrored) {
     draw_image_mirrored_ = mirrored;
   }
 
+  void SetPadding(const gfx::Insets& padding);

[sky, 2017/03/16 04:12:42]

SetPadding makes it sound like this is setting something in addition to the
border, which isn't the case. I would rather callers explicitly set the border.
Less confusion as what SetBorder(...) does and less duplicate ways of doing the
same thing.

+
   // Overridden from View:
   gfx::Size GetPreferredSize() const override;
   const char* GetClassName() const override;
   void OnPaint(gfx::Canvas* canvas) override;
 
  protected:
   // Overridden from View:
   void OnFocus() override;
   void OnBlur() override;
 
@@ skipping 80 matching lines @@
   // The parent class's tooltip_text_ is displayed when not toggled, and
   // this one is shown when toggled.
   base::string16 toggled_tooltip_text_;
 
   DISALLOW_COPY_AND_ASSIGN(ToggleImageButton);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_BUTTON_IMAGE_BUTTON_H_