chromeos: Refactor shelf to create ShelfView earlier in startup

ash/shelf/wm_shelf.h

Index: ash/shelf/wm_shelf.h
diff --git a/ash/shelf/wm_shelf.h b/ash/shelf/wm_shelf.h
index 491f35e1b3ae4369371787afdf5671ffad546928..78eb18be4cf06aa5149cfe4a035859567eb7a349 100644
--- a/ash/shelf/wm_shelf.h
+++ b/ash/shelf/wm_shelf.h
@@ -33,8 +33,9 @@ class StatusAreaWidget;
 class WmShelfObserver;
 class WmWindow;
 
-// Controller for the shelf state. Exists for the lifetime of each root window
-// controller. Note that the shelf widget may not be created until after login.

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

This bit about the widget was a lie.

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

Acknowledged.

+// Controller for the shelf state. One per display, because each display might
+// have different shelf alignment, autohide, etc. Exists for the lifetime of the
+// root window controller.
 class ASH_EXPORT WmShelf : public ShelfLayoutManagerObserver {

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

Should we rename this to Shelf at some point? :D

[James Cook, 2017/05/17 16:16:13]

Yeah. Or ShelfController (and merge with the existing ShelfController? or rename
that one too?).

Whee, renames.

We should talk about when to do this. Now-ish would be good, since we're right
before the branch.

  public:
   WmShelf();
@@ -58,14 +59,8 @@ class ASH_EXPORT WmShelf : public ShelfLayoutManagerObserver {
 
   ShelfWidget* shelf_widget() { return shelf_widget_.get(); }
 
-  // Creates the shelf view.
-  void CreateShelfView();
-
   // TODO(jamescook): Eliminate this method.
-  void ShutdownShelf();
-
-  // True after the ShelfView has been created (e.g. after login).
-  bool IsShelfInitialized() const;
+  void NotifyShelfInitialized();
 
   // Returns the window showing the shelf.
   WmWindow* GetWindow();
@@ -159,10 +154,6 @@ class ASH_EXPORT WmShelf : public ShelfLayoutManagerObserver {
 
   std::unique_ptr<ShelfWidget> shelf_widget_;
 
-  // Internal implementation detail. Do not expose externally. Owned by views
-  // hierarchy. Null before login and in secondary display init.
-  ShelfView* shelf_view_ = nullptr;
-
   // These initial values hide the shelf until user preferences are available.
   ShelfAlignment alignment_ = SHELF_ALIGNMENT_BOTTOM_LOCKED;
   ShelfAutoHideBehavior auto_hide_behavior_ = SHELF_AUTO_HIDE_ALWAYS_HIDDEN;