ash: Remove ash::Shelf in favor of ash::WmShelf

ash/common/shelf/wm_shelf.h

Index: ash/common/shelf/wm_shelf.h
diff --git a/ash/common/shelf/wm_shelf.h b/ash/common/shelf/wm_shelf.h
index a785551596b4ccbb2e4b29517b9e753b0e22ab18..b5630618e463d2a4490a03c62fafdc7a2dd927fb 100644
--- a/ash/common/shelf/wm_shelf.h
+++ b/ash/common/shelf/wm_shelf.h
@@ -22,7 +22,6 @@ class GestureEvent;
 
 namespace ash {
 
-class Shelf;
 class ShelfLayoutManager;
 class ShelfLockingManager;
 class ShelfView;
@@ -40,10 +39,7 @@ class ASH_EXPORT WmShelf : public ShelfLayoutManagerObserver {
   // widget may not exist, or the shelf may not be visible.
   static WmShelf* ForWindow(WmWindow* window);
 
-  void SetShelf(Shelf* shelf);
-  void ClearShelf();
-  Shelf* shelf() const { return shelf_; }
-
+  // TODO(jamescook): Create the ShelfLayoutManager in this class.
   virtual void SetShelfLayoutManager(ShelfLayoutManager* manager);
   ShelfLayoutManager* shelf_layout_manager() const {
     return shelf_layout_manager_;
@@ -51,6 +47,14 @@ class ASH_EXPORT WmShelf : public ShelfLayoutManagerObserver {
 
   ShelfWidget* shelf_widget() { return shelf_widget_; }
 
+  // Creates the shelf view.
+  // TODO(jamescook): Make this create the shelf widget instead.

[msw, 2016/08/30 22:02:07]

nit: I'm not sure about this TODO; it might make sense to just create the
ShelfWidget and ShelfView in the ctor and keep them invisible as we discussed.
Perhaps you've thought more about this, but I'm not sure delaying widget
creation makes sense.

[James Cook, 2016/08/30 23:00:56]

Removed the comment. I'm still not sure about the right thing to do here. If we
create the ShelfView with WmShelf we'll be creating it at the login screen
before the user profile is loaded, and we'll be running code in
ChromeLauncherControllerImpl that expects the user to be logged in. We could
work around that, but it might be easier to go the other way and defer creation
of the ShelfWidget. I'm not sure yet, so I removed the comment.

+  void CreateShelf();

[msw, 2016/08/30 22:02:07]

nit: "InitializeShelf" or similar?

[James Cook, 2016/08/30 23:00:57]

Done.

+  void DestroyShelf();

[msw, 2016/08/30 22:02:07]

nit: "ShutdownShelf" or similar?

[James Cook, 2016/08/30 23:00:57]

Done.

+
+  // True after the ShelfView has been created (e.g. after login).
+  bool IsShelfCreated() const;

[msw, 2016/08/30 22:02:07]

optional nit: "IsShelfInitialized" or similar?

[James Cook, 2016/08/30 23:00:57]

Done.

+
   // Returns the window showing the shelf.
   WmWindow* GetWindow();
 
@@ -148,10 +152,6 @@ class ASH_EXPORT WmShelf : public ShelfLayoutManagerObserver {
                            BackgroundAnimatorChangeType change_type) override;
 
  private:
-  // Legacy shelf controller. Null before login and in secondary display init.
-  // Instance lifetimes are managed by ash::RootWindowController and WmShelfMus.
-  Shelf* shelf_ = nullptr;
-
   // Layout manager for the shelf container window. Instances are constructed by
   // ShelfWidget and lifetimes are managed by the container windows themselves.
   ShelfLayoutManager* shelf_layout_manager_ = nullptr;
@@ -159,6 +159,10 @@ class ASH_EXPORT WmShelf : public ShelfLayoutManagerObserver {
   // TODO(jamescook): Move ShelfWidget ownership here.
   ShelfWidget* shelf_widget_ = nullptr;
 
+  // Internal implementation detail. Do not expose externally. Owned by views
+  // hierarchy. Null before login and in secondary display init.
+  ShelfView* shelf_view_ = nullptr;
+
   ShelfAlignment alignment_ = SHELF_ALIGNMENT_BOTTOM_LOCKED;
 
   // Sets shelf alignment to bottom during login and screen lock.