chromeos: Refactor shelf to create ShelfView earlier in startup

ash/shelf/shelf_layout_manager.cc

Index: ash/shelf/shelf_layout_manager.cc
diff --git a/ash/shelf/shelf_layout_manager.cc b/ash/shelf/shelf_layout_manager.cc
index 19deab0a039b3bbec21e718d8e84468befbb781a..98672563e90e8090e43b516d69290511b33e1546 100644
--- a/ash/shelf/shelf_layout_manager.cc
+++ b/ash/shelf/shelf_layout_manager.cc
@@ -234,10 +234,16 @@ ShelfVisibilityState ShelfLayoutManager::CalculateShelfVisibility() {
 }
 
 void ShelfLayoutManager::UpdateVisibilityState() {
-  // Bail out early before the shelf is initialized or after it is destroyed.
-  WmWindow* shelf_window = WmWindow::Get(shelf_widget_->GetNativeWindow());
-  if (in_shutdown_ || !wm_shelf_->IsShelfInitialized() || !shelf_window)
+  // Shelf is not available before login.
+  // TODO: Remove this when webui fake-shelf is replaced with views.

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

nit: cite the bug, consider "  // TODO(crbug.com/######): Remove this when
login/lock use the real shelf." or similar? ditto below (line 896)

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

Done.

+  if (!Shell::Get()->session_controller()->IsActiveUserSessionStarted())
+    return;
+
+  // Bail out early after shelf is destroyed.
+  aura::Window* shelf_window = shelf_widget_->GetNativeWindow();
+  if (in_shutdown_ || !shelf_window)

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

It's unclear if the shelf_window check is needed but I don't want to touch it.

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

Acknowledged.

     return;
+
   if (state_.IsScreenLocked() || state_.IsAddingSecondaryUser()) {
     SetState(SHELF_VISIBLE);
   } else if (Shell::Get()->screen_pinning_controller()->IsPinned()) {
@@ -246,7 +252,8 @@ void ShelfLayoutManager::UpdateVisibilityState() {
     // TODO(zelidrag): Verify shelf drag animation still shows on the device
     // when we are in SHELF_AUTO_HIDE_ALWAYS_HIDDEN.
     wm::WorkspaceWindowState window_state(
-        shelf_window->GetRootWindowController()->GetWorkspaceWindowState());
+        RootWindowController::ForWindow(shelf_window)
+            ->GetWorkspaceWindowState());
 
     switch (window_state) {
       case wm::WORKSPACE_WINDOW_STATE_FULL_SCREEN: {
@@ -884,7 +891,12 @@ bool ShelfLayoutManager::HasVisibleWindow() const {
 
 ShelfAutoHideState ShelfLayoutManager::CalculateAutoHideState(
     ShelfVisibilityState visibility_state) const {
-  if (visibility_state != SHELF_AUTO_HIDE || !wm_shelf_->IsShelfInitialized())
+  // Shelf is not available before login.
+  // TODO: Remove this when webui fake-shelf is replaced with views.
+  if (!Shell::Get()->session_controller()->IsActiveUserSessionStarted())
+    return SHELF_AUTO_HIDE_HIDDEN;
+
+  if (visibility_state != SHELF_AUTO_HIDE)
     return SHELF_AUTO_HIDE_HIDDEN;
 
   if (shelf_widget_->IsShowingAppList())