chromeos: Refactor shelf to create ShelfView earlier in startup

ash/shelf/shelf_locking_manager.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/shelf/shelf_locking_manager.h"
 
 #include "ash/session/session_controller.h"
 #include "ash/shelf/wm_shelf.h"
 #include "ash/shell.h"
 #include "ash/shell_port.h"
 
 namespace ash {
 
 ShelfLockingManager::ShelfLockingManager(WmShelf* shelf)
     : shelf_(shelf),
-      stored_alignment_(shelf->GetAlignment()),
+      stored_alignment_(SHELF_ALIGNMENT_BOTTOM_LOCKED),

[James Cook, 2017/05/16 21:32:35]

This is to avoid reading out of a partially-constructed WmShelf.

[msw, 2017/05/16 22:42:00]

Acknowledged.

       scoped_session_observer_(this) {
   DCHECK(shelf_);
   ShellPort::Get()->AddLockStateObserver(this);
   SessionController* controller = Shell::Get()->session_controller();
   session_locked_ =
       controller->GetSessionState() != session_manager::SessionState::ACTIVE;
   screen_locked_ = controller->IsScreenLocked();
 }
 
 ShelfLockingManager::~ShelfLockingManager() {
@@ skipping 21 matching lines @@
   const ShelfAlignment alignment = shelf_->GetAlignment();
   if (is_locked() && alignment != SHELF_ALIGNMENT_BOTTOM_LOCKED) {
     stored_alignment_ = alignment;
     shelf_->SetAlignment(SHELF_ALIGNMENT_BOTTOM_LOCKED);
   } else if (!is_locked() && alignment == SHELF_ALIGNMENT_BOTTOM_LOCKED) {
     shelf_->SetAlignment(stored_alignment_);
   }
 }
 
 }  // namespace ash