ash: Some code-cleanup around tray-resizing code.

ash/system/tray/tray_item_view.cc

Index: ash/system/tray/tray_item_view.cc
diff --git a/ash/system/tray/tray_item_view.cc b/ash/system/tray/tray_item_view.cc
index ddb9f314381914707b0724151e116361da094824..0984e22e8e7a0d4a7a6f3959d3f0fb4546d3725b 100644
--- a/ash/system/tray/tray_item_view.cc
+++ b/ash/system/tray/tray_item_view.cc
@@ -62,12 +62,6 @@ void TrayItemView::SetVisible(bool set_visible) {
   }
 }
 
-void TrayItemView::ApplyChange() {
-  // Forcing the widget to the new size is sufficient. The positioning is
-  // taken care of by the layout manager (ShelfLayoutManager).
-  GetWidget()->SetSize(GetWidget()->GetContentsView()->GetPreferredSize());
-}
-
 gfx::Size TrayItemView::DesiredSize() {
   return views::View::GetPreferredSize();
 }
@@ -76,11 +70,6 @@ int TrayItemView::GetAnimationDurationMS() {
   return kTrayItemAnimationDurationMS;
 }
 
-void TrayItemView::PreferredSizeChanged() {
-  views::View::PreferredSizeChanged();
-  ApplyChange();
-}
-
 gfx::Size TrayItemView::GetPreferredSize() {
   gfx::Size size = DesiredSize();
   size.set_height(kTrayIconHeight);
@@ -91,6 +80,10 @@ gfx::Size TrayItemView::GetPreferredSize() {
   return size;
 }
 
+void TrayItemView::ChildPreferredSizeChanged(views::View* child) {
+  PreferredSizeChanged();
+}
+
 void TrayItemView::AnimationProgressed(const ui::Animation* animation) {
   ui::Transform transform;
   transform.SetScale(animation->GetCurrentValue(),
@@ -98,7 +91,7 @@ void TrayItemView::AnimationProgressed(const ui::Animation* animation) {
   transform.ConcatTranslate(0, animation->CurrentValueBetween(
       static_cast<double>(height()) / 2, 0.));
   layer()->SetTransform(transform);
-  ApplyChange();
+  PreferredSizeChanged();
 }
 
 void TrayItemView::AnimationEnded(const ui::Animation* animation) {