Update shelf when overlapping dragged windows exist

ash/wm/dock/docked_window_layout_manager.cc

Index: ash/wm/dock/docked_window_layout_manager.cc
diff --git a/ash/wm/dock/docked_window_layout_manager.cc b/ash/wm/dock/docked_window_layout_manager.cc
index b3c9ebece7c8fdf7a5bc3e47077cb12154fb0d99..d51c2968036d46e244c52c6a5b4227e64e979fe7 100644
--- a/ash/wm/dock/docked_window_layout_manager.cc
+++ b/ash/wm/dock/docked_window_layout_manager.cc
@@ -483,6 +483,10 @@ void DockedWindowLayoutManager::SetChildBounds(
     const gfx::Rect& requested_bounds) {
   // Whenever one of our windows is moved or resized enforce layout.
   SetChildBoundsDirect(child, requested_bounds);
+  ShelfLayoutManager* shelf_layout = internal::ShelfLayoutManager::ForLauncher(
+      dock_container_);
+  if (shelf_layout)

[oshima, 2013/12/03 17:31:28]

I forgot to ask.

Can this be NULL?

[varkha, 2013/12/03 18:01:27]

In Ash it can only be NULL during startup or shutdown, and docked layout manager
lifetime seems to be enclosed in shelf lifetime (see
RootWindowController::InitLayoutManagers). I just didn't want to assume this
dependency following what I see elsewhere in the code such as here
https://code.google.com/p/chromium/codesearch#chromium/src/ash/wm/workspace/w....

[oshima, 2013/12/03 18:08:49]

I believe this is from ancient spec where shelf was only on primary display.
This is fine for now, but we probably should revisit this later.

+    shelf_layout->UpdateVisibilityState();
 }
 
 ////////////////////////////////////////////////////////////////////////////////