aura: Fix applist crash on 2nd show.

r120147 accidentally removed widget observer instead of the animation observer.

BUG=112654
TEST=Verify fix for issue 112654.


Review URL: http://codereview.chromium.org/9331007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@120722 0039d316-1c4b-4281-b951-d872f2087c98

ash/app_list/app_list.cc

@@ -87,7 +87,7 @@ void AppList::SetWidget(views::Widget* widget) {
 
   if (is_visible_) {
     widget_ = widget;
-    GetLayer(widget_)->GetAnimator()->AddObserver(this);
+    widget_->AddObserver(this);
     Shell::GetInstance()->AddRootWindowEventFilter(this);
 
     widget_->SetBounds(GetPreferredBounds(false));