[Views] Update ink drop for omnibox icons

ui/views/animation/ink_drop.cc

 // 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.
 
 #include "ui/views/animation/ink_drop.h"
 
 namespace views {
 
+InkDrop::~InkDrop() {}
+
+void InkDrop::AddObserver(InkDropObserver* observer) {
+  CHECK(observer);
+  observers_.AddObserver(observer);
+}
+
+void InkDrop::RemoveObserver(InkDropObserver* observer) {
+  CHECK(observer);
+  observers_.RemoveObserver(observer);
+}
+
+InkDrop::InkDrop() {}
+
 InkDropContainerView::InkDropContainerView() {}
 
 void InkDropContainerView::AddInkDropLayer(ui::Layer* ink_drop_layer) {
   SetPaintToLayer();
   SetVisible(true);
   layer()->SetFillsBoundsOpaquely(false);
   layer()->Add(ink_drop_layer);
 }
 
 void InkDropContainerView::RemoveInkDropLayer(ui::Layer* ink_drop_layer) {
   layer()->Remove(ink_drop_layer);
   SetVisible(false);
   DestroyLayer();
 }
 
 bool InkDropContainerView::CanProcessEventsWithinSubtree() const {
   // Ensure the container View is found as the EventTarget instead of this.
   return false;
 }
 
 }  // namespace views