Enhanced the InkDropRippleImpl to create/destroy InkDropAnimations as needed.

ui/views/animation/ink_drop_animation_controller_impl.cc

 // Copyright 2015 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_animation_controller_impl.h"
 
 #include "ui/views/animation/ink_drop_animation.h"
 #include "ui/views/animation/ink_drop_host.h"
 
 namespace views {
 
 InkDropAnimationControllerImpl::InkDropAnimationControllerImpl(
     InkDropHost* ink_drop_host)
     : ink_drop_host_(ink_drop_host) {}
 
 InkDropAnimationControllerImpl::~InkDropAnimationControllerImpl() {
-  if (ink_drop_animation_) {
-    // TODO(bruthig): Change this to be called when the ink drop becomes hidden.
-    // See www.crbug.com/522175.
-    ink_drop_host_->RemoveInkDropLayer(ink_drop_animation_->root_layer());
-  }
+  // Explicitly destroy the InkDropAnimation so that this still exists if
+  // views::InkDropAnimationObserver methods are called on this.
+  DestroyInkDropAnimation();
 }
 
 InkDropState InkDropAnimationControllerImpl::GetInkDropState() const {
   if (!ink_drop_animation_)
     return InkDropState::HIDDEN;
   return ink_drop_animation_->ink_drop_state();
 }
 
-void InkDropAnimationControllerImpl::AnimateToState(InkDropState state) {
+void InkDropAnimationControllerImpl::AnimateToState(
+    InkDropState ink_drop_state) {
   if (!ink_drop_animation_)
     CreateInkDropAnimation();
-  ink_drop_animation_->AnimateToState(state);
+  ink_drop_animation_->AnimateToState(ink_drop_state);
 }
 
 gfx::Size InkDropAnimationControllerImpl::GetInkDropLargeSize() const {
   return ink_drop_large_size_;
 }
 
 void InkDropAnimationControllerImpl::SetInkDropSize(const gfx::Size& large_size,
                                                     int large_corner_radius,
                                                     const gfx::Size& small_size,
                                                     int small_corner_radius) {
@@ skipping 10 matching lines @@
 }
 
 void InkDropAnimationControllerImpl::SetInkDropCenter(
     const gfx::Point& center_point) {
   ink_drop_center_ = center_point;
   if (ink_drop_animation_)
     ink_drop_animation_->SetCenterPoint(ink_drop_center_);
 }
 
 void InkDropAnimationControllerImpl::CreateInkDropAnimation() {
-  if (ink_drop_animation_)
-    ink_drop_host_->RemoveInkDropLayer(ink_drop_animation_->root_layer());
+  DestroyInkDropAnimation();
 
-  // TODO(bruthig): It will be expensive to maintain InkDropAnimation instances
-  // when they are not actually being used. Consider creating InkDropAnimations
-  // on an as-needed basis and if construction is also expensive then consider
-  // creating an InkDropAnimationPool. See www.crbug.com/522175.
   ink_drop_animation_.reset(new InkDropAnimation(
       ink_drop_large_size_, ink_drop_large_corner_radius_, ink_drop_small_size_,
       ink_drop_small_corner_radius_));
 
+  ink_drop_animation_->AddObserver(this);
   ink_drop_animation_->SetCenterPoint(ink_drop_center_);
   ink_drop_host_->AddInkDropLayer(ink_drop_animation_->root_layer());
 }
 
+void InkDropAnimationControllerImpl::DestroyInkDropAnimation() {
+  if (!ink_drop_animation_)
+    return;
+  ink_drop_host_->RemoveInkDropLayer(ink_drop_animation_->root_layer());
+  ink_drop_animation_->RemoveObserver(this);
+  ink_drop_animation_.reset();
+}
+
+void InkDropAnimationControllerImpl::InkDropAnimationStarted(
+    InkDropState ink_drop_state) {}
+
+void InkDropAnimationControllerImpl::InkDropAnimationEnded(
+    InkDropState ink_drop_state,
+    InkDropAnimationEndedReason reason) {
+  if (reason != SUCCESS)
+    return;
+  switch (ink_drop_state) {
+    case views::InkDropState::QUICK_ACTION:
+    case views::InkDropState::SLOW_ACTION:
+    case views::InkDropState::DEACTIVATED:
+      ink_drop_animation_->AnimateToState(views::InkDropState::HIDDEN);
+      break;
+    case views::InkDropState::HIDDEN:
+      // TODO(bruthig): Investigate whether creating and destroying
+      // InkDropAnimations is expensive and consider creating an
+      // InkDropAnimationPool. See www.crbug.com/522175.
+      DestroyInkDropAnimation();
+      break;
+    default:
+      break;
+  }
+}
+
 }  // namespace views