chromeos: Refactor shelf to create ShelfView earlier in startup

chrome/browser/chromeos/accessibility/chromevox_panel.cc

 // Copyright 2015 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 "chrome/browser/chromeos/accessibility/chromevox_panel.h"
 
 #include "ash/accessibility_types.h"
 #include "ash/public/cpp/shell_window_ids.h"
 #include "ash/root_window_controller.h"
 #include "ash/shelf/shelf_layout_manager.h"
@@ skipping 114 matching lines @@
 void ChromeVoxPanel::Close() {
   widget_->Close();
 }
 
 void ChromeVoxPanel::DidFirstVisuallyNonEmptyPaint() {
   widget_->Show();
   UpdatePanelHeight();
 }
 
 void ChromeVoxPanel::UpdatePanelHeight() {
-  ash::WmShelf* shelf =
-      ash::WmShelf::ForWindow(ash::WmWindow::Get(GetRootWindow()));
-  if (!shelf->IsShelfInitialized())
-    return;
+  SendPanelHeightToAsh(kPanelHeight);
+}
 
-  ash::ShelfLayoutManager* shelf_layout_manager = shelf->shelf_layout_manager();
-  if (shelf_layout_manager)
-    shelf_layout_manager->SetChromeVoxPanelHeight(kPanelHeight);
+void ChromeVoxPanel::ResetPanelHeight() {
+  SendPanelHeightToAsh(0);
 }
 
 void ChromeVoxPanel::EnterFullscreen() {
   Focus();
   panel_fullscreen_ = true;
   UpdateWidgetBounds();
 }
 
 void ChromeVoxPanel::ExitFullscreen() {
   widget_->Deactivate();
@@ skipping 42 matching lines @@
   // If we're in full-screen mode, give the panel a height of 0 unless
   // it's active.
   if (ash::GetRootWindowController(GetRootWindow())
           ->GetWindowForFullscreenMode() &&
       !widget_->IsActive()) {
     bounds.set_height(0);
   }
 
   widget_->SetBounds(bounds);
 }
+
+void ChromeVoxPanel::SendPanelHeightToAsh(int panel_height) {
+  // WmShelf is available for the lifetime of the RootWindowController.
+  ash::RootWindowController* root_window_controller =
+      ash::RootWindowController::ForWindow(GetRootWindow());
+  if (!root_window_controller)
+    return;
+
+  // TODO(mash): Replace with shelf mojo API.
+  ash::ShelfLayoutManager* shelf_layout_manager =
+      root_window_controller->GetShelf()->shelf_layout_manager();
+  if (shelf_layout_manager)
+    shelf_layout_manager->SetChromeVoxPanelHeight(panel_height);
+}