chromeos: Refactor shelf to create ShelfView earlier in startup

ash/root_window_controller.cc

 // Copyright (c) 2012 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/root_window_controller.h"
 
 #include <algorithm>
 #include <queue>
 #include <vector>
 
@@ skipping 341 matching lines @@
 }
 
 bool RootWindowController::HasShelf() {
   return wm_shelf_->shelf_widget() != nullptr;
 }
 
 WmShelf* RootWindowController::GetShelf() {
   return wm_shelf_.get();
 }
 
-void RootWindowController::CreateShelfView() {
-  if (wm_shelf_->IsShelfInitialized())
+void RootWindowController::InitializeShelf() {
+  if (shelf_initialized_)
     return;
-  wm_shelf_->CreateShelfView();
+  shelf_initialized_ = true;
+  wm_shelf_->NotifyShelfInitialized();
 
   // TODO(jamescook): Pass |wm_shelf_| into the constructors for these layout
   // managers.
   if (panel_layout_manager_)
     panel_layout_manager_->SetShelf(wm_shelf_.get());
 
-  // Notify shell observers that the shelf has been created.
-  // TODO(jamescook): Move this into WmShelf::InitializeShelf(). This will
-  // require changing AttachedPanelWidgetTargeter's access to WmShelf.
+  // TODO(jamescook): Eliminate this. Refactor AttachedPanelWidgetTargeter's
+  // access to WmShelf.
   Shell::Get()->NotifyShelfCreatedForRootWindow(WmWindow::Get(GetRootWindow()));
 
   wm_shelf_->shelf_widget()->PostCreateShelf();
 }
 
 ShelfLayoutManager* RootWindowController::GetShelfLayoutManager() {
   return wm_shelf_->shelf_layout_manager();
 }
 
 SystemModalContainerLayoutManager*
@@ skipping 209 matching lines @@
   while (!root->GetChildren().empty()) {
     WmWindow* child = root->GetChildren()[0];
     if (ShouldDestroyWindowInCloseChildWindows(child))
       child->Destroy();
     else
       root->RemoveChild(child);
   }
 
   shelf->DestroyShelfWidget();
 
-  // CloseChildWindows() may be called twice during the shutdown of ash
-  // unittests. Avoid notifying WmShelf that the shelf has been destroyed twice.
-  if (shelf->IsShelfInitialized())
-    shelf->ShutdownShelf();
-
   aura::client::SetDragDropClient(GetRootWindow(), nullptr);
   aura::client::SetTooltipClient(GetRootWindow(), nullptr);
 }
 
 void RootWindowController::MoveWindowsTo(aura::Window* dst) {
   // Clear the workspace controller, so it doesn't incorrectly update the shelf.
   workspace_controller_.reset();
   ReparentAllWindows(GetRootWindow(), dst);
 }
 
@@ skipping 141 matching lines @@
 
   shell->AddShellObserver(this);
 
   root_window_layout_manager_->OnWindowResized();
   if (root_window_type == RootWindowType::PRIMARY) {
     if (Shell::GetAshConfig() != Config::MASH)
       shell->InitKeyboard();
   } else {
     window_tree_host_->Show();
 
-    // Create a shelf if a user is already logged in.
-    if (shell->session_controller()->NumberOfLoggedInUsers())
-      CreateShelfView();
+    // At the login screen the shelf will be hidden because its container
+    // window is hidden.

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

nit: Maybe tie this comment into Shelf init? (eg. "... hidden; InitializeShelf
will make it visible.")

[James Cook, 2017/05/17 16:16:12]

Done.

+    InitializeShelf();
 
     // Notify shell observers about new root window.
     shell->OnRootWindowAdded(WmWindow::Get(root_window));
   }
 
   // TODO: AshTouchExplorationManager doesn't work with mus.
   // http://crbug.com/679782
   if (!base::CommandLine::ForCurrentProcess()->HasSwitch(
           switches::kAshDisableTouchExplorationMode) &&
       Shell::GetAshConfig() != Config::MASH) {
@@ skipping 314 matching lines @@
     EnableTouchHudProjection();
   else
     DisableTouchHudProjection();
 }
 
 RootWindowController* GetRootWindowController(const aura::Window* root_window) {
   return root_window ? GetRootWindowSettings(root_window)->controller : nullptr;
 }
 
 }  // namespace ash