ash: Explicitly teach various components about ShelfLayoutManager.

ash/system/web_notification/ash_popup_alignment_delegate.h

Index: ash/system/web_notification/ash_popup_alignment_delegate.h
diff --git a/ash/system/web_notification/ash_popup_alignment_delegate.h b/ash/system/web_notification/ash_popup_alignment_delegate.h
index 5e37ea7ba686e7cf0acda1b22f34adb3aae7d689..d4dbffac670cdba6b0a11f13502627f9dc4b83a3 100644
--- a/ash/system/web_notification/ash_popup_alignment_delegate.h
+++ b/ash/system/web_notification/ash_popup_alignment_delegate.h
@@ -38,7 +38,7 @@ class ASH_EXPORT AshPopupAlignmentDelegate
       public ShellObserver,
       public gfx::DisplayObserver {
  public:
-  AshPopupAlignmentDelegate();
+  explicit AshPopupAlignmentDelegate(ShelfLayoutManager* shelf);
   ~AshPopupAlignmentDelegate() override;
 
   // Start observing the system.
@@ -63,11 +63,6 @@ class ASH_EXPORT AshPopupAlignmentDelegate
   // Get the current alignment of the shelf.
   ShelfAlignment GetAlignment() const;
 
-  // Update |shelf_| and start watching when it's first set. This should not
-  // be done in the constructor because the shelf might not be initialized at
-  // that point.
-  void UpdateShelf();
-
   // Utility function to get the display which should be care about.
   gfx::Display GetCurrentDisplay() const;