Allow InkDropRipple to co-exist with highlight

ui/views/animation/empty_ink_drop_ripple.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_EMPTY_INK_DROP_RIPPLE_H_
+#define UI_VIEWS_ANIMATION_EMPTY_INK_DROP_RIPPLE_H_
+
+#include "ui/views/animation/ink_drop_ripple.h"
+
+namespace views {
+
+// A no-op ink drop ripple which permits an InkDropHost to have an
+// InkDropHighlight. For use with surfaces that want a highlight but no ripple.
+class VIEWS_EXPORT EmptyInkDropRipple : public InkDropRipple {
+ public:
+  EmptyInkDropRipple();
+  ~EmptyInkDropRipple() override;
+
+  // InkDropRipple:
+  void AnimateToState(InkDropState ink_drop_state) override;
+  void SnapToActivated() override;
+  ui::Layer* GetRootLayer() override;
+  bool OverridesHighlight() const override;
+
+ protected:
+  // InkDropRipple:
+  void AnimateStateChange(InkDropState old_ink_drop_state,
+                          InkDropState new_ink_drop_state,
+                          ui::LayerAnimationObserver* observer) override;
+  void SetStateToHidden() override;
+  void AbortAllAnimations() override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(EmptyInkDropRipple);
+};
+
+}  // namespace views
+
+#endif  // UI_VIEWS_ANIMATION_EMPTY_INK_DROP_RIPPLE_H_