Status Trays delayed visibility

ash/shelf/shelf_layout_manager.cc

Index: ash/shelf/shelf_layout_manager.cc
diff --git a/ash/shelf/shelf_layout_manager.cc b/ash/shelf/shelf_layout_manager.cc
index 0d6713b15feb21df009f6147a2b125bd33b6e8ab..3c15ea7fddf27187346cff3865e360f8278fcbf0 100644
--- a/ash/shelf/shelf_layout_manager.cc
+++ b/ash/shelf/shelf_layout_manager.cc
@@ -652,6 +652,11 @@ void ShelfLayoutManager::UpdateBoundsAndOpacity(
     ui::ImplicitAnimationObserver* observer) {
   base::AutoReset<bool> auto_reset_updating_bounds(&updating_bounds_, true);
 
+  // Setting visibility after enabling animations cause the visibile property to
+  // animate. Enable visibility here so that opacity can animate.
+  if (target_bounds.status_opacity)
+    shelf_->status_area_widget()->Show();

[flackr, 2014/09/23 19:14:03]

This doesn't cause the invalid window state (Visible window with 0 opacity)
updating visibility before we've set target opacity?

If you call show after setting up the opacity animation, but outside of the
scope of the ScopedLayerAnimationSettings it should not have the invalid state.

[jonross, 2014/09/23 20:50:06]

This apparently does trigger an invalid state, however it seems that it should.

Window::Show() performs the invalid state checks before calling
SetVisible(true). So a window can be set to visible=false and opacity=0, then
Show() would trigger visible=true and opacity=0 after the current check.

[jonross, 2014/09/23 21:06:20]

Moved it for correctness.

+
   ui::ScopedLayerAnimationSettings shelf_animation_setter(
       GetLayer(shelf_)->GetAnimator());
   ui::ScopedLayerAnimationSettings status_animation_setter(
@@ -686,11 +691,9 @@ void ShelfLayoutManager::UpdateBoundsAndOpacity(
       target_bounds.status_opacity);
 
   // Having a window which is visible but does not have an opacity is an illegal
-  // state. We therefore show / hide the shelf here if required.
+  // state. We therefore hide the shelf here if required.
   if (!target_bounds.status_opacity)
     shelf_->status_area_widget()->Hide();
-  else if (target_bounds.status_opacity)
-    shelf_->status_area_widget()->Show();
 
   // TODO(harrym): Once status area widget is a child view of shelf
   // this can be simplified.