chromeos: Refactor shelf to create ShelfView earlier in startup

ash/root_window_controller.h

Index: ash/root_window_controller.h
diff --git a/ash/root_window_controller.h b/ash/root_window_controller.h
index 6f0945fd821330bad199472a4581507d4bd73ec5..e0ff96964ad0e9e55f675994394899e3e84f0977 100644
--- a/ash/root_window_controller.h
+++ b/ash/root_window_controller.h
@@ -139,12 +139,14 @@ class ASH_EXPORT RootWindowController : public ShellObserver {
 
   WmShelf* wm_shelf() const { return wm_shelf_.get(); }
 
+  // TODO(jamescook): Eliminate this. It always returns true after the

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

nit: There's only two occurrences, maybe just do this now by inlining
wm_shelf()->shelf_widget()? (we should also combine |wm_shelf()| and
|GetShelf()| down the line)

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

Done. As I suspected, it wasn't needed at all.

+  // layout managers are initialized.
   bool HasShelf();
 
   WmShelf* GetShelf();
 
-  // Creates the shelf view for this root window and notifies observers.
-  void CreateShelfView();
+  // Initializes the shelf for this root window and notifies observers.
+  void InitializeShelf();
 
   // Get touch HUDs associated with this root window controller.
   TouchHudDebug* touch_hud_debug() const { return touch_hud_debug_; }
@@ -352,6 +354,10 @@ class ASH_EXPORT RootWindowController : public ShellObserver {
   // to it during construction of the shelf widget and status tray.
   std::unique_ptr<WmShelf> wm_shelf_;
 
+  // TODO(jamescook): Eliminate this. It is left over from legacy shelf code and
+  // doesn't mean anything in particular.
+  bool shelf_initialized_ = false;
+
   std::unique_ptr<SystemWallpaperController> system_wallpaper_;
 
   std::unique_ptr<BootSplashScreen> boot_splash_screen_;