Fix a leak in wm::AnimateOnChildWindowVisibilityChanged().

ui/wm/core/window_animations.cc

Index: ui/wm/core/window_animations.cc
diff --git a/ui/wm/core/window_animations.cc b/ui/wm/core/window_animations.cc
index a79db3a15d6c45a76d6cdb78a8e3e7dc2db5035a..22fd43d387406c69d776c7c2344b5a7a895541ef 100644
--- a/ui/wm/core/window_animations.cc
+++ b/ui/wm/core/window_animations.cc
@@ -58,7 +58,8 @@ const float kWindowAnimation_Vertical_TranslateY = 15.f;
 // The subclass will determine when the animation is completed.
 class HidingWindowAnimationObserverBase : public aura::WindowObserver {
  public:
-  HidingWindowAnimationObserverBase(aura::Window* window) : window_(window) {
+  explicit HidingWindowAnimationObserverBase(aura::Window* window)
+      : window_(window) {
     window_->AddObserver(this);
   }
   virtual ~HidingWindowAnimationObserverBase() {
@@ -396,31 +397,29 @@ class RotateHidingWindowAnimationObserver
     : public HidingWindowAnimationObserverBase,
       public ui::LayerAnimationObserver {
  public:
-  RotateHidingWindowAnimationObserver(aura::Window* window)
-      : HidingWindowAnimationObserverBase(window), last_sequence_(NULL) {}
+  explicit RotateHidingWindowAnimationObserver(aura::Window* window)
+      : HidingWindowAnimationObserverBase(window) {}
   virtual ~RotateHidingWindowAnimationObserver() {}
 
-  void set_last_sequence(ui::LayerAnimationSequence* last_sequence) {
-    last_sequence_ = last_sequence;
+  // Destroys itself after |last_sequence| ends or is aborted. Does not take
+  // ownership of |last_sequence|, which should not be NULL.
+  void SetLastSequence(ui::LayerAnimationSequence* last_sequence) {
+    last_sequence->AddObserver(this);
   }
 
   // ui::LayerAnimationObserver:
   virtual void OnLayerAnimationEnded(
       ui::LayerAnimationSequence* sequence) OVERRIDE {
-    if (last_sequence_ == sequence)
-      OnAnimationCompleted();
+    OnAnimationCompleted();
   }
   virtual void OnLayerAnimationAborted(
       ui::LayerAnimationSequence* sequence) OVERRIDE {
-    if (last_sequence_ == sequence)
-      OnAnimationCompleted();
+    OnAnimationCompleted();
   }
   virtual void OnLayerAnimationScheduled(
       ui::LayerAnimationSequence* sequence) OVERRIDE {}
 
  private:
-  ui::LayerAnimationSequence* last_sequence_;
-
   DISALLOW_COPY_AND_ASSIGN(RotateHidingWindowAnimationObserver);
 };
 
@@ -482,8 +481,9 @@ void AddLayerAnimationsForRotate(aura::Window* window, bool show) {
   ui::LayerAnimationSequence* last_sequence =
       new ui::LayerAnimationSequence(transition.release());
   window->layer()->GetAnimator()->ScheduleAnimation(last_sequence);
+
   if (observer) {
-    observer->set_last_sequence(last_sequence);
+    observer->SetLastSequence(last_sequence);
     observer->DetachAndRecreateLayers();
   }
 }