CustomButton: restrict animation repaints to buttons that actually animate

ui/views/controls/button/custom_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_CUSTOM_BUTTON_H_
 #define UI_VIEWS_CONTROLS_BUTTON_CUSTOM_BUTTON_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 134 matching lines @@
   void set_has_ink_drop_action_on_click(bool has_ink_drop_action_on_click) {
     has_ink_drop_action_on_click_ = has_ink_drop_action_on_click;
   }
 
   // Returns true if the button should enter hovered state; that is, if the
   // mouse is over the button, and no other window has capture (which would
   // prevent the button from receiving MouseExited events and updating its
   // state). This does not take into account enabled state.
   bool ShouldEnterHoveredState();
 
+  void set_animates_hover(bool animates) { animates_hover_ = animates; }
+  bool animates_hover() { return animates_hover_; }
+
   // Overridden from Button:
   void NotifyClick(const ui::Event& event) override;
   void OnClickCanceled(const ui::Event& event) override;
 
   const gfx::ThrobAnimation& hover_animation() const {
     return hover_animation_;
   }
 
  private:
   ButtonState state_;
@@ skipping 19 matching lines @@
   // ink_drop_delegate().
   bool has_ink_drop_action_on_click_;
 
   // When true, the ink drop ripple and hover will be hidden prior to showing
   // the context menu.
   bool hide_ink_drop_when_showing_context_menu_;
 
   // The color of the ripple and hover.
   SkColor ink_drop_base_color_;
 
+  // Whether this button has a hover effect. If this returns true, painting the

[sky, 2016/10/11 19:17:45]

As you mentioned previously, it seems wrong that an animation would be started
and nothing visually changes. This makes me question the usefullness of having
CustomButton have the animation. Is it possible to move the animation entirely
to the subclass? What class is starting an animation but has no visual change
when the animation ticks?

+  // button is taken to be dependent on the animation state and SchedulePaint()
+  // is called as the hover animation progresses.
+  bool animates_hover_ = false;
+
   DISALLOW_COPY_AND_ASSIGN(CustomButton);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_CONTROLS_BUTTON_CUSTOM_BUTTON_H_