Color the ink drop ripple and hover effects based on theming.

ui/views/animation/ink_drop_host_view.h

 // Copyright 2016 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_ANIMATION_INK_DROP_HOST_VIEW_H_
 #define UI_VIEWS_ANIMATION_INK_DROP_HOST_VIEW_H_
 
 #include "base/memory/scoped_ptr.h"
+#include "third_party/skia/include/core/SkColor.h"
 #include "ui/views/animation/ink_drop_host.h"
 #include "ui/views/view.h"
 
 namespace views {
 
 class InkDropAnimation;
 class InkDropHover;
 
 // A view that provides InkDropHost functionality.
 class VIEWS_EXPORT InkDropHostView : public views::View, public InkDropHost {
  public:
   InkDropHostView();
   ~InkDropHostView() override;
 
   // Overridden from views::InkDropHost:
   void AddInkDropLayer(ui::Layer* ink_drop_layer) override;
   void RemoveInkDropLayer(ui::Layer* ink_drop_layer) override;
   scoped_ptr<InkDropAnimation> CreateInkDropAnimation() const override;
   scoped_ptr<InkDropHover> CreateInkDropHover() const override;
 
  protected:
   // Overrideable methods to allow views to provide minor tweaks to the default
   // ink drop.
   virtual gfx::Point GetInkDropCenter() const;
+  virtual SkColor GetInkDropBaseColor() const;

[sky, 2016/02/25 00:38:32]

As your implementation has a NOTREACHED, is there a reason you didn't want to
make this pure virtual?

[Evan Stade, 2016/02/25 01:34:28]

yes, originally it was pure virtual, but there was a test button class that
inherited from Button which complained. I figured it would be valid to create a
button that didn't have a ripple, and if no ripple is added this should never be
called. If this is never called, it's annoying to have to provide an override.

 
  private:
   DISALLOW_COPY_AND_ASSIGN(InkDropHostView);
 };
 }
 
 #endif  // UI_VIEWS_ANIMATION_INK_DROP_HOST_VIEW_H_