[Views] Update ink drop for omnibox icons

ui/views/animation/ink_drop_observer.h

+// Copyright 2017 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_OBSERVER_H_
+#define UI_VIEWS_ANIMATION_INK_DROP_OBSERVER_H_
+
+#include <string>
+
+#include "base/macros.h"
+#include "ui/views/views_export.h"
+
+namespace views {
+
+// Observer to attach to an InkDrop.
+class VIEWS_EXPORT InkDropObserver {
+ public:
+  // Called when the animation of the current InkDrop has started. This
+  // includes the ripple or highlight animation.
+  virtual void InkDropAnimationStarted() = 0;
+
+ protected:
+  InkDropObserver() = default;
+  virtual ~InkDropObserver() = default;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(InkDropObserver);
+};
+
+}  // namespace views
+
+#endif  // UI_VIEWS_ANIMATION_INK_DROP_OBSERVER_H_