ash: Explicitly teach various components about ShelfLayoutManager.

ash/system/web_notification/ash_popup_alignment_delegate.cc

Index: ash/system/web_notification/ash_popup_alignment_delegate.cc
diff --git a/ash/system/web_notification/ash_popup_alignment_delegate.cc b/ash/system/web_notification/ash_popup_alignment_delegate.cc
index 84e21a9f99d3610a1ad2c00d8350a9247beb3bfe..e8dc463ddff2a07fb614d51aaa76bee984c90179 100644
--- a/ash/system/web_notification/ash_popup_alignment_delegate.cc
+++ b/ash/system/web_notification/ash_popup_alignment_delegate.cc
@@ -32,8 +32,9 @@ const int kNoToastMarginBorderAndShadowOffset = 2;
 
 }
 
-AshPopupAlignmentDelegate::AshPopupAlignmentDelegate()
-    : screen_(NULL), root_window_(NULL), shelf_(NULL), system_tray_height_(0) {
+AshPopupAlignmentDelegate::AshPopupAlignmentDelegate(ShelfLayoutManager* shelf)
+    : screen_(NULL), root_window_(NULL), shelf_(shelf), system_tray_height_(0) {
+  shelf_->AddObserver(this);
 }
 
 AshPopupAlignmentDelegate::~AshPopupAlignmentDelegate() {
@@ -51,7 +52,6 @@ void AshPopupAlignmentDelegate::StartObserving(gfx::Screen* screen,
   root_window_ = ash::Shell::GetInstance()
                      ->window_tree_host_manager()
                      ->GetRootWindowForDisplayId(display.id());
-  UpdateShelf();
   screen->AddObserver(this);
   Shell::GetInstance()->AddShellObserver(this);
   if (system_tray_height_ > 0)
@@ -120,15 +120,6 @@ ShelfAlignment AshPopupAlignmentDelegate::GetAlignment() const {
   return shelf_ ? shelf_->GetAlignment() : SHELF_ALIGNMENT_BOTTOM;
 }
 
-void AshPopupAlignmentDelegate::UpdateShelf() {
-  if (shelf_)
-    return;
-
-  shelf_ = ShelfLayoutManager::ForShelf(root_window_);
-  if (shelf_)
-    shelf_->AddObserver(this);
-}
-
 gfx::Display AshPopupAlignmentDelegate::GetCurrentDisplay() const {
   return gfx::Screen::GetScreen()->GetDisplayNearestWindow(
       shelf_->shelf_widget()->GetNativeView());
@@ -140,7 +131,6 @@ void AshPopupAlignmentDelegate::UpdateWorkArea() {
 }
 
 void AshPopupAlignmentDelegate::OnDisplayWorkAreaInsetsChanged() {
-  UpdateShelf();
   UpdateWorkArea();
 }
 
@@ -165,7 +155,6 @@ void AshPopupAlignmentDelegate::OnDisplayRemoved(
 void AshPopupAlignmentDelegate::OnDisplayMetricsChanged(
     const gfx::Display& display,
     uint32_t metrics) {
-  UpdateShelf();
   if (shelf_ && GetCurrentDisplay().id() == display.id())
     UpdateWorkArea();
 }