mash: Replace ShelfItemDelegate::CanPin with ShelfItem::pinned_by_policy.

ash/common/shelf/shelf_item_delegate.h

Index: ash/common/shelf/shelf_item_delegate.h
diff --git a/ash/common/shelf/shelf_item_delegate.h b/ash/common/shelf/shelf_item_delegate.h
index ab13a83fe1c7093a00a949a230d89c54b5d1642d..868e8561b319a3a847b0949923171326be197fb2 100644
--- a/ash/common/shelf/shelf_item_delegate.h
+++ b/ash/common/shelf/shelf_item_delegate.h
@@ -47,11 +47,6 @@ class ASH_EXPORT ShelfItemDelegate {
   // Returns the title to display.
   virtual base::string16 GetTitle() = 0;
 
-  // Returns whether the user can change the pin status of this item.
-  // Pinning may be disallowed by policy if this app is pinned by pre-defined
-  // pinned app list.
-  virtual bool CanPin() const = 0;
-
   // Returns the application menu model for the specified item. There are three
   // possible return values:
   //  - A return of NULL indicates that no menu is wanted for this item.