Tweaks to "Allow InkDropRipple to co-exist with highlight or not exist at all."

ui/views/animation/ink_drop_ripple.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_ripple.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "ui/base/ui_base_switches.h"
@@ skipping 24 matching lines @@
   // two reasons.
   // 1. The attached observers must be notified of all animations started and
   // ended.
   // 2. Not all state transitions is are valid, especially no-op transitions,
   // and these should be detected by DCHECKs in AnimateStateChange().
 
   // |animation_observer| will be deleted when AnimationEndedCallback() returns
   // true.
   // TODO(bruthig): Implement a safer ownership model for the
   // |animation_observer|.
   ui::CallbackLayerAnimationObserver* animation_observer =

[Evan Stade, 2016/09/20 15:16:29]

what happens to animation_observer when !GetRootLayer()?

[bruthig, 2016/09/20 16:17:16]

A test would be the best way to know for sure, but I'm expecting the
|animation_observer| doesn't get any LayerAnimations added to it and when
SetActive() is called on line 67 it will invoke the callbacks synchronously.

       new ui::CallbackLayerAnimationObserver(
           base::Bind(&InkDropRipple::AnimationStartedCallback,
                      base::Unretained(this), ink_drop_state),
           base::Bind(&InkDropRipple::AnimationEndedCallback,
                      base::Unretained(this), ink_drop_state));
 
   InkDropState old_ink_drop_state = target_ink_drop_state_;
   // Assign to |target_ink_drop_state_| before calling AnimateStateChange() so
   // that any observers notified as a side effect of the AnimateStateChange()
   // will get the target InkDropState when calling GetInkDropState().
   target_ink_drop_state_ = ink_drop_state;
 
-  if (old_ink_drop_state == InkDropState::HIDDEN &&
-      target_ink_drop_state_ != InkDropState::HIDDEN) {
-    GetRootLayer()->SetVisible(true);
+  if (GetRootLayer()) {
+    if (old_ink_drop_state == InkDropState::HIDDEN &&
+        target_ink_drop_state_ != InkDropState::HIDDEN) {
+      GetRootLayer()->SetVisible(true);
+    }
+
+    AnimateStateChange(old_ink_drop_state, target_ink_drop_state_,
+                       animation_observer);
   }
-
-  AnimateStateChange(old_ink_drop_state, target_ink_drop_state_,
-                     animation_observer);
   animation_observer->SetActive();
   // |this| may be deleted! |animation_observer| might synchronously call
   // AnimationEndedCallback which can delete |this|.
 }
 
 void InkDropRipple::SnapToActivated() {
   AbortAllAnimations();
   // |animation_observer| will be deleted when AnimationEndedCallback() returns
   // true.
   // TODO(bruthig): Implement a safer ownership model for the
   // |animation_observer|.
   ui::CallbackLayerAnimationObserver* animation_observer =
       new ui::CallbackLayerAnimationObserver(
           base::Bind(&InkDropRipple::AnimationStartedCallback,
                      base::Unretained(this), InkDropState::ACTIVATED),
           base::Bind(&InkDropRipple::AnimationEndedCallback,
                      base::Unretained(this), InkDropState::ACTIVATED));
-  GetRootLayer()->SetVisible(true);
+  if (GetRootLayer())
+    GetRootLayer()->SetVisible(true);
   target_ink_drop_state_ = InkDropState::ACTIVATED;
   animation_observer->SetActive();
 }
 
+bool InkDropRipple::IsVisible() {
+  return GetRootLayer() && GetRootLayer()->visible();
+}
+
 void InkDropRipple::HideImmediately() {
   AbortAllAnimations();
   SetStateToHidden();
   target_ink_drop_state_ = InkDropState::HIDDEN;
 }
 
 test::InkDropRippleTestApi* InkDropRipple::GetTestApi() {
   return nullptr;
 }
 
 void InkDropRipple::AnimationStartedCallback(
     InkDropState ink_drop_state,
     const ui::CallbackLayerAnimationObserver& observer) {
-  observer_->AnimationStarted(ink_drop_state);
+  if (observer_)
+    observer_->AnimationStarted(ink_drop_state);
 }
 
 bool InkDropRipple::AnimationEndedCallback(
     InkDropState ink_drop_state,
     const ui::CallbackLayerAnimationObserver& observer) {
   if (ink_drop_state == InkDropState::HIDDEN)
     SetStateToHidden();
-  observer_->AnimationEnded(ink_drop_state,
-                            observer.aborted_count()
-                                ? InkDropAnimationEndedReason::PRE_EMPTED
-                                : InkDropAnimationEndedReason::SUCCESS);
-  // |this| may be deleted!
+  if (observer_) {
+    observer_->AnimationEnded(ink_drop_state,
+                              observer.aborted_count()
+                                  ? InkDropAnimationEndedReason::PRE_EMPTED
+                                  : InkDropAnimationEndedReason::SUCCESS);
+    // |this| may be deleted!
+  }
   return true;
 }
 
 }  // namespace views