ash: Move AppList support to ShelfWidget, expose ShelfWidget in 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 6f5a64f3b50eb0b07c9b1971eef005f745c173d7..a785551596b4ccbb2e4b29517b9e753b0e22ab18 100644
--- a/ash/common/shelf/wm_shelf.h
+++ b/ash/common/shelf/wm_shelf.h
@@ -49,6 +49,8 @@ class ASH_EXPORT WmShelf : public ShelfLayoutManagerObserver {
     return shelf_layout_manager_;
   }
 
+  ShelfWidget* shelf_widget() { return shelf_widget_; }
+
   // Returns the window showing the shelf.
   WmWindow* GetWindow();
 
@@ -133,7 +135,6 @@ class ASH_EXPORT WmShelf : public ShelfLayoutManagerObserver {
   void SetVirtualKeyboardBoundsForTesting(const gfx::Rect& bounds);
   ShelfLockingManager* GetShelfLockingManagerForTesting();
   ShelfView* GetShelfViewForTesting();
-  ShelfWidget* GetShelfWidgetForTesting();
 
  protected:
   WmShelf();
@@ -155,6 +156,9 @@ class ASH_EXPORT WmShelf : public ShelfLayoutManagerObserver {
   // ShelfWidget and lifetimes are managed by the container windows themselves.
   ShelfLayoutManager* shelf_layout_manager_ = nullptr;
 
+  // TODO(jamescook): Move ShelfWidget ownership here.
+  ShelfWidget* shelf_widget_ = nullptr;
+
   ShelfAlignment alignment_ = SHELF_ALIGNMENT_BOTTOM_LOCKED;
 
   // Sets shelf alignment to bottom during login and screen lock.