Fix a crash in dtor of CallbackAnimationObserver

ui/keyboard/keyboard_controller.cc

 // Copyright (c) 2013 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/keyboard/keyboard_controller.h"
 
 #include <set>
 
 #include "base/bind.h"
 #include "base/command_line.h"
@@ skipping 106 matching lines @@
  public:
   CallbackAnimationObserver(ui::LayerAnimator* animator,
                             base::Callback<void(void)> callback);
   ~CallbackAnimationObserver() override;
 
  private:
   // Overridden from ui::LayerAnimationObserver:
   void OnLayerAnimationEnded(ui::LayerAnimationSequence* seq) override;
   void OnLayerAnimationAborted(ui::LayerAnimationSequence* seq) override;
   void OnLayerAnimationScheduled(ui::LayerAnimationSequence* seq) override {}
+  bool RequiresNotificationWhenAnimatorDestroyed() const override;
 
   ui::LayerAnimator* animator_;

[sadrul, 2015/04/23 23:07:59]

Should this be a scoped_refptr<> instead?

[bshe, 2015/04/24 14:24:37]

Great suggestion! Done.

   base::Callback<void(void)> callback_;
 
   DISALLOW_COPY_AND_ASSIGN(CallbackAnimationObserver);
 };
 
 CallbackAnimationObserver::CallbackAnimationObserver(
     ui::LayerAnimator* animator, base::Callback<void(void)> callback)
     : animator_(animator), callback_(callback) {
 }
 
 CallbackAnimationObserver::~CallbackAnimationObserver() {
-  animator_->RemoveObserver(this);
+  if (animator_)
+    animator_->RemoveObserver(this);
 }
 
 void CallbackAnimationObserver::OnLayerAnimationEnded(
     ui::LayerAnimationSequence* seq) {
   if (animator_->is_animating())
     return;
   animator_->RemoveObserver(this);
   callback_.Run();
+  animator_ = NULL;
 }
 
 void CallbackAnimationObserver::OnLayerAnimationAborted(
     ui::LayerAnimationSequence* seq) {
   animator_->RemoveObserver(this);
+  animator_ = NULL;
+}
+
+bool CallbackAnimationObserver::RequiresNotificationWhenAnimatorDestroyed()
+    const {
+  return true;
 }
 
 class WindowBoundsChangeObserver : public aura::WindowObserver {
  public:
   void OnWindowBoundsChanged(aura::Window* window,
                              const gfx::Rect& old_bounds,
                              const gfx::Rect& new_bounds) override;
   void OnWindowDestroyed(aura::Window* window) override;
 
   void AddObservedWindow(aura::Window* window);
@@ skipping 405 matching lines @@
   proxy_->HideKeyboardContainer(container_.get());
 }
 
 void KeyboardController::AddBoundsChangedObserver(aura::Window* window) {
   aura::Window* target_window = window ? window->GetToplevelWindow() : nullptr;
   if (target_window)
     window_bounds_observer_->AddObservedWindow(target_window);
 }
 
 }  // namespace keyboard