LayerAnimator must be prepared for its owning layer's deletion whenever it notifies observers.

ui/compositor/layer_animator.cc

 // Copyright (c) 2012 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/compositor/layer_animator.h"
 
 #include "base/debug/trace_event.h"
 #include "base/logging.h"
 #include "base/memory/scoped_ptr.h"
 #include "ui/base/animation/animation_container.h"
@@ skipping 20 matching lines @@
   static ui::AnimationContainer* container = NULL;
   if (!container) {
     container = new AnimationContainer();
     container->AddRef();
   }
   return container;
 }
 
 }  // namespace
 
-class LayerAnimator::DestroyedTracker
-    : public base::RefCounted<LayerAnimator::DestroyedTracker> {
- public:
-  DestroyedTracker() : is_alive_(true) {}
-
-  // Returns true if the animator is still alive.
-  bool is_alive() const { return is_alive_; }
-
-  // Invoked when the animator is destroyed.
-  void AnimatorDeleted() {
-    DCHECK(is_alive_);
-    is_alive_ = false;
-  }
-
- private:
-  friend class base::RefCounted<DestroyedTracker>;
-
-  ~DestroyedTracker() {
-    DCHECK(!is_alive_);
-  }
-
-  bool is_alive_;
-
-  DISALLOW_COPY_AND_ASSIGN(DestroyedTracker);
-};
-
 // static
 bool LayerAnimator::disable_animations_for_test_ = false;
 // static
 bool LayerAnimator::slow_animation_mode_ = false;
 // static
 int LayerAnimator::slow_animation_scale_factor_ = 4;
 
 // LayerAnimator public --------------------------------------------------------
 
 LayerAnimator::LayerAnimator(base::TimeDelta transition_duration)
     : delegate_(NULL),
       preemption_strategy_(IMMEDIATELY_SET_NEW_TARGET),
       transition_duration_(transition_duration),
       tween_type_(Tween::LINEAR),
       is_started_(false),
-      disable_timer_for_test_(false),
-      destroyed_tracker_(new DestroyedTracker) {
+      disable_timer_for_test_(false) {
 }
 
 LayerAnimator::~LayerAnimator() {
   for (size_t i = 0; i < running_animations_.size(); ++i)
     running_animations_[i].sequence->OnAnimatorDestroyed();
-  ClearAnimations();
-  destroyed_tracker_->AnimatorDeleted();
+  ClearAnimationsInternal();
+  delegate_ = NULL;
 }
 
 // static
 LayerAnimator* LayerAnimator::CreateDefaultAnimator() {
   return new LayerAnimator(base::TimeDelta::FromMilliseconds(0));
 }
 
 // static
 LayerAnimator* LayerAnimator::CreateImplicitAnimator() {
   return new LayerAnimator(kDefaultTransitionDuration);
@@ skipping 78 matching lines @@
   StartAnimation(new LayerAnimationSequence(element.release()));
 }
 
 float LayerAnimator::GetTargetGrayscale() const {
   LayerAnimationElement::TargetValue target(delegate());
   GetTargetValue(&target);
   return target.grayscale;
 }
 
 void LayerAnimator::SetDelegate(LayerAnimationDelegate* delegate) {
-  DCHECK(delegate);
   delegate_ = delegate;
 }
 
 void LayerAnimator::StartAnimation(LayerAnimationSequence* animation) {
+  scoped_refptr<LayerAnimator> retain(this);
   OnScheduled(animation);
   if (!StartSequenceImmediately(animation)) {
     // Attempt to preempt a running animation.
     switch (preemption_strategy_) {
       case IMMEDIATELY_SET_NEW_TARGET:
         ImmediatelySetNewTarget(animation);
         break;
       case IMMEDIATELY_ANIMATE_TO_NEW_TARGET:
         ImmediatelyAnimateToNewTarget(animation);
         break;
       case ENQUEUE_NEW_ANIMATION:
         EnqueueNewAnimation(animation);
         break;
       case REPLACE_QUEUED_ANIMATIONS:
         ReplaceQueuedAnimations(animation);
         break;
       case BLEND_WITH_CURRENT_ANIMATION: {
         // TODO(vollick) Add support for blended sequences and use them here.
         NOTIMPLEMENTED();
         break;
       }
     }
   }
   FinishAnyAnimationWithZeroDuration();
   UpdateAnimationState();
 }
 
 void LayerAnimator::ScheduleAnimation(LayerAnimationSequence* animation) {
+  scoped_refptr<LayerAnimator> retain(this);
   OnScheduled(animation);
   if (is_animating()) {
     animation_queue_.push_back(make_linked_ptr(animation));
     ProcessQueue();
   } else {
     StartSequenceImmediately(animation);
   }
   UpdateAnimationState();
 }
 
 void LayerAnimator::ScheduleTogether(
     const std::vector<LayerAnimationSequence*>& animations) {
+  scoped_refptr<LayerAnimator> retain(this);
+
   // Collect all the affected properties.
   LayerAnimationElement::AnimatableProperties animated_properties;
   std::vector<LayerAnimationSequence*>::const_iterator iter;
   for (iter = animations.begin(); iter != animations.end(); ++iter) {
     animated_properties.insert((*iter)->properties().begin(),
                                (*iter)->properties().end());
   }
 
   // Scheduling a zero duration pause that affects all the animated properties
   // will prevent any of the sequences from animating until there are no
@@ skipping 35 matching lines @@
     if ((*queue_iter)->properties().find(property) !=
         (*queue_iter)->properties().end()) {
       return true;
     }
   }
   return false;
 }
 
 void LayerAnimator::StopAnimatingProperty(
     LayerAnimationElement::AnimatableProperty property) {
+  scoped_refptr<LayerAnimator> retain(this);
   while (true) {
     RunningAnimation* running = GetRunningAnimation(property);
     if (!running)
       break;
-    if (FinishAnimation(running->sequence) == DESTROYED)
-      return;
+    FinishAnimation(running->sequence);
   }
 }
 
 void LayerAnimator::StopAnimating() {
-  while (is_animating()) {
-    if (FinishAnimation(running_animations_[0].sequence) == DESTROYED)
-      return;
-  }
+  scoped_refptr<LayerAnimator> retain(this);
+  while (is_animating())
+    FinishAnimation(running_animations_[0].sequence);
 }
 
 void LayerAnimator::AddObserver(LayerAnimationObserver* observer) {
   if (!observers_.HasObserver(observer))
     observers_.AddObserver(observer);
 }
 
 void LayerAnimator::RemoveObserver(LayerAnimationObserver* observer) {
   observers_.RemoveObserver(observer);
   // Remove the observer from all sequences as well.
   for (AnimationQueue::iterator queue_iter = animation_queue_.begin();
        queue_iter != animation_queue_.end(); ++queue_iter) {
     (*queue_iter)->RemoveObserver(observer);
   }
 }
 
 // LayerAnimator protected -----------------------------------------------------
 
-bool LayerAnimator::ProgressAnimation(LayerAnimationSequence* sequence,
+void LayerAnimator::ProgressAnimation(LayerAnimationSequence* sequence,
                                       base::TimeDelta delta) {
-  return sequence->Progress(delta, delegate());
+  if (!delegate())
+    return;
+
+  sequence->Progress(delta, delegate());
 }
 
 
 bool LayerAnimator::HasAnimation(LayerAnimationSequence* sequence) const {
   for (AnimationQueue::const_iterator queue_iter = animation_queue_.begin();
        queue_iter != animation_queue_.end(); ++queue_iter) {
     if ((*queue_iter).get() == sequence)
       return true;
   }
   return false;
 }
 
 // LayerAnimator private -------------------------------------------------------
 
 void LayerAnimator::Step(base::TimeTicks now) {
   TRACE_EVENT0("ui", "LayerAnimator::Step");
+  scoped_refptr<LayerAnimator> retain(this);
 
   last_step_time_ = now;
 
   // We need to make a copy of the running animations because progressing them
   // and finishing them may indirectly affect the collection of running
   // animations.
   RunningAnimations running_animations_copy = running_animations_;
-  bool needs_redraw = false;
   for (size_t i = 0; i < running_animations_copy.size(); ++i) {
     if (!HasAnimation(running_animations_copy[i].sequence))
       continue;
 
     base::TimeDelta delta = now - running_animations_copy[i].start_time;
     if (delta >= running_animations_copy[i].sequence->duration() &&
         !running_animations_copy[i].sequence->is_cyclic()) {
-      if (FinishAnimation(running_animations_copy[i].sequence) == DESTROYED)
-        return;
-      needs_redraw = true;
-    } else {
-      scoped_refptr<DestroyedTracker> tracker(destroyed_tracker_);
-      const bool progress_result =
-          ProgressAnimation(running_animations_copy[i].sequence, delta);
-      if (!tracker->is_alive())
-        return;
-      if (progress_result)
-        needs_redraw = true;
-    }
+      FinishAnimation(running_animations_copy[i].sequence);
+    } else
+      ProgressAnimation(running_animations_copy[i].sequence, delta);
   }
-
-  if (needs_redraw && delegate())
-    delegate()->ScheduleDrawForAnimation();
 }
 
 void LayerAnimator::SetStartTime(base::TimeTicks start_time) {
   // Do nothing.
 }
 
 base::TimeDelta LayerAnimator::GetTimerInterval() const {
   return kTimerInterval;
 }
 
@@ skipping 29 matching lines @@
     if ((*queue_iter) == sequence) {
       to_return = *queue_iter;
       animation_queue_.erase(queue_iter);
       break;
     }
   }
 
   return to_return.release();
 }
 
-LayerAnimator::DestroyedType LayerAnimator::FinishAnimation(
-    LayerAnimationSequence* sequence) {
+void LayerAnimator::FinishAnimation(LayerAnimationSequence* sequence) {
+  scoped_refptr<LayerAnimator> retain(this);
   scoped_ptr<LayerAnimationSequence> removed(RemoveAnimation(sequence));
-  {
-    scoped_refptr<DestroyedTracker> tracker(destroyed_tracker_);
+  if (delegate())
     sequence->Progress(sequence->duration(), delegate());
-    if (!tracker->is_alive())
-      return DESTROYED;
-  }
   ProcessQueue();
   UpdateAnimationState();
-  return NOT_DESTROYED;
 }
 
 void LayerAnimator::FinishAnyAnimationWithZeroDuration() {
+  scoped_refptr<LayerAnimator> retain(this);
   // Special case: if we've started a 0 duration animation, just finish it now
   // and get rid of it. We need to make a copy because Progress may indirectly
   // cause new animations to start running.
   RunningAnimations running_animations_copy = running_animations_;
   for (size_t i = 0; i < running_animations_copy.size(); ++i) {
     if (!HasAnimation(running_animations_copy[i].sequence))
       continue;
 
     if (running_animations_copy[i].sequence->duration() == base::TimeDelta()) {
-      running_animations_copy[i].sequence->Progress(
-          running_animations_copy[i].sequence->duration(), delegate());
+      ProgressAnimation(running_animations_copy[i].sequence,
+                        running_animations_copy[i].sequence->duration());
       scoped_ptr<LayerAnimationSequence> removed(
           RemoveAnimation(running_animations_copy[i].sequence));
     }
   }
   ProcessQueue();
   UpdateAnimationState();
 }
 
 void LayerAnimator::ClearAnimations() {
-  // Abort should never affect the set of running animations, but just in case
-  // clients are badly behaved, we will use a copy of the running animations.
-  RunningAnimations running_animations_copy = running_animations_;
-  for (size_t i = 0; i < running_animations_copy.size(); ++i) {
-    if (!HasAnimation(running_animations_copy[i].sequence))
-      continue;
-
-    scoped_ptr<LayerAnimationSequence> removed(
-        RemoveAnimation(running_animations_copy[i].sequence));
-    if (removed.get())
-      removed->Abort();
-  }
-  // This *should* have cleared the list of running animations.
-  DCHECK(running_animations_.empty());
-  running_animations_.clear();
-  animation_queue_.clear();
-  UpdateAnimationState();
+  scoped_refptr<LayerAnimator> retain(this);
+  ClearAnimationsInternal();
 }
 
 LayerAnimator::RunningAnimation* LayerAnimator::GetRunningAnimation(
     LayerAnimationElement::AnimatableProperty property) {
   for (RunningAnimations::iterator iter = running_animations_.begin();
        iter != running_animations_.end(); ++iter) {
     if ((*iter).sequence->properties().find(property) !=
         (*iter).sequence->properties().end())
       return &(*iter);
   }
@@ skipping 26 matching lines @@
     if (!HasAnimation(running_animations_copy[i].sequence))
       continue;
 
     if (running_animations_copy[i].sequence->HasCommonProperty(
             sequence->properties())) {
       scoped_ptr<LayerAnimationSequence> removed(
           RemoveAnimation(running_animations_copy[i].sequence));
       if (abort)
         running_animations_copy[i].sequence->Abort();
       else
-        running_animations_copy[i].sequence->Progress(
-            running_animations_copy[i].sequence->duration(), delegate());
+        ProgressAnimation(running_animations_copy[i].sequence,
+                          running_animations_copy[i].sequence->duration());
     }
   }
 
   // Same for the queued animations that haven't been started. Again, we'll
   // need to operate on a copy.
   std::vector<LayerAnimationSequence*> sequences;
   for (AnimationQueue::iterator queue_iter = animation_queue_.begin();
        queue_iter != animation_queue_.end(); ++queue_iter)
     sequences.push_back((*queue_iter).get());
 
   for (size_t i = 0; i < sequences.size(); ++i) {
     if (!HasAnimation(sequences[i]))
       continue;
 
     if (sequences[i]->HasCommonProperty(sequence->properties())) {
       scoped_ptr<LayerAnimationSequence> removed(
           RemoveAnimation(sequences[i]));
       if (abort)
         sequences[i]->Abort();
       else
-        sequences[i]->Progress(sequences[i]->duration(), delegate());
+        ProgressAnimation(sequences[i], sequences[i]->duration());
     }
   }
 }
 
 void LayerAnimator::ImmediatelySetNewTarget(LayerAnimationSequence* sequence) {
   // Ensure that sequence is disposed of when this function completes.
   scoped_ptr<LayerAnimationSequence> to_dispose(sequence);
   const bool abort = false;
   RemoveAllAnimationsWithACommonProperty(sequence, abort);
   LayerAnimationSequence* removed = RemoveAnimation(sequence);
   DCHECK(removed == NULL || removed == sequence);
-  sequence->Progress(sequence->duration(), delegate());
+  ProgressAnimation(sequence, sequence->duration());
 }
 
 void LayerAnimator::ImmediatelyAnimateToNewTarget(
     LayerAnimationSequence* sequence) {
   const bool abort = true;
   RemoveAllAnimationsWithACommonProperty(sequence, abort);
   AddToQueueIfNotPresent(sequence);
   StartSequenceImmediately(sequence);
 }
 
@@ skipping 122 matching lines @@
       sequence->AddObserver(obs);
     }
   }
   sequence->OnScheduled();
 }
 
 base::TimeDelta LayerAnimator::GetTransitionDuration() const {
   return transition_duration_;
 }
 
+void LayerAnimator::ClearAnimationsInternal() {
+  // Abort should never affect the set of running animations, but just in case
+  // clients are badly behaved, we will use a copy of the running animations.
+  RunningAnimations running_animations_copy = running_animations_;
+  for (size_t i = 0; i < running_animations_copy.size(); ++i) {
+    if (!HasAnimation(running_animations_copy[i].sequence))
+      continue;
+
+    scoped_ptr<LayerAnimationSequence> removed(
+        RemoveAnimation(running_animations_copy[i].sequence));
+    if (removed.get())
+      removed->Abort();
+  }
+  // This *should* have cleared the list of running animations.
+  DCHECK(running_animations_.empty());
+  running_animations_.clear();
+  animation_queue_.clear();
+  UpdateAnimationState();
+}
+
 }  // namespace ui